Turns after all this time I actually missed one species, E. barbata, one with zero observations at this time (although I hope to change that later this year), I did also improve a few other species in this newest version. More information in version 1.0: https://www.inaturalist.org/journal/eleodesthermopolis/87075-v1-0-a-key-to-the-eleodes-species-of-the-united-states-and-canada-outdated

1 Mesofemora and metafemora dentate or subdentate...2
1’ Mesofemora and metafemora never dentate...4
2 Elytral punctures strongly muricate...E. moesta
2’ Elytral punctures simple or slightly muricate...3
3 Pronotum widest anterior of middle, femoral spines large...E. armata
3’ Pronotum widest at middle, femoral spines small to medium sized...E. femorata
4 Body small, pronotum generally cordate and constricted at base, elytra apex not attenuate or caudate, roughly sculptured, distributed across beaches, forests, and mountains...subgenus Blapylis
4’ Body small or large, pronotum usually not cordate although often slightly constricted at base, elytral apex attenuate, caudate or neither, roughly sculptured or not, widespread across all environments...5
5 Legs long with unproportionately small body, robust or not, body often flattened if not robust...6
5’ Legs long or short but with body fairly proportionate, only rarely flattened...22
6 Body generally slender and flattened, pronotal and elytral sculpturing simple (except in E. nigrina)...7
6’ Body, generally robust, never flattened, pronotal and elytral sculpturing complex...18
7 Elytral sculpturing muricate or scabrous...E. nigrina (in part)
7’ Elytral sculpturing simple...8
8 Range only in Inyo White Mountains...9
8’ Range widespread...10
9 Profemora with large tooth, anterolateral angles blunt but projected...E. aalbui
9’ Profemora only sinuate, anterolateral angles slightly projected...E. microps
10 Range near Big Bend National Park and the Guadalupe Mountains...11
10’ Range in the Southwest United States excluding Texas and the Guadalupe Mountains...13
11 Range in the Guadalupe Mountains...E. guadalupensis
11’ Range in Big Bend National Park...12
12 Mentum with finger-like process, pronotum subquadrate, widest at middle...E. labialis
12’ Mentum without finger-like process, pronotum widest anterior to middle...E. easterlai
13 Range in the Mohave Desert of California, pronotum usually evenly arcuate...E. californica
13’ Range in Arizona, Utah, and Sonora, pronotum rarely evenly arcuate...14
14 Range in the Sonoran desert or the most western portion of the Arizona-Utah border...15
14’ Range in the Sky Islands or the Colorado Plateau...16
15 Anterolateral angles strongly projected, caves by the most western point of the Arizona-Utah border…E. wynnei
15’ Anterolateral angles not strongly projected, the Sonoran desert…E. delicata (E. nevadensis)
16 Body elongate, northern Arizona and southern Utah...17
16’ Body not elongate, Sky Islands in southeast Arizona...E. dissimilis
17 Strial punctures larger than punctures of intervals, restricted to the Grand Canyon...E. leptoscelis
17’ Strial punctures subequal to punctures of intervals, northern Arizona and southern Utah...E. wheeleri
18 Large tubercles present on Elytra...19
18’ Elytra without large tubercules...20
19 Range in Sierra Nevada region...E. granosa
19’ Range near the Four Corners...E. leechi
20 Pronotum evenly tuberculate, range in Oregon...E. spoliata
20’ Pronotum punctate, range widespread...21
21 Antennas robust, body generally more robust...E. hirsuta
21’ Antennas thin, body generally more slender...E. pilosa
22 Size small or sometimes medium, covered in long setae, restricted to coastal California and the Baja peninsula, and the Sonoran desert...23
22’ Size small or large, usually glabrous, if with conspicuous setae then not found in coastal California, nor in the Baja peninsula or the Sonoran desert...28
23 Males with dentate profemora and elytra caudate, Sonoran desert...E. tribulus
23’ Males nor females ever caudate or attenuate, coastal California and the Baja peninsula...24
24 Third antennomere shortened, body smaller and more slender...E. littoralis
24’ Third antennomere not shorted, body larger...25
25 Body larger, pronotum with constriction at base, if missing constriction then setae more dense...26
25’ Body smaller, pronotum lacking constriction at base, setae less dense...27
26 Setae orange, California and northern Baja peninsula...E. osculans
26’ Setae black or grey, California and northern Baja peninsula...E. ursus
27 Setae black, California and northern Baja peninsula...E. nigropilosa
27’ Setae yellow, Baja peninsula...E. subdeplanata
28 Elytra caudate at least in males and strongly muricate, near Tamaulipas if not caudate, size usually large...29
28’ Elytra caudate or not, but if caudate and muricately punctured then elytra only slightly muricate, elytra can be strongly muricate if not caudate and not near Tamaulipas, size large or small...31
29 Only males caudate with profemora dentate, Tamaulipas...E. fiski
29’ Both males and females caudate with mutic profemora, Four Corners and Sierra Nevada region...30
30 Elytra usually glabrous, rarely with setae, Four Corners...E. caudifera
30’ Elytra always with long setae, Sierra Nevada region...E. longipilosa
31 Elytral sculpture very rough, elytra always attenuate but never caudate, restricted to California...32
31’ Elytral sculpture variable but if rough then elytra never attenuate, widespread...33
32 Luster shiny and elytral apex acutely attenuate...E. marginata
32’ Luster dull and elytral apex blunt yet still attenuate...E. scabricula (E. acutangula)
33 Body oval shaped, coated in minute setae, coastal Texas and Louisiana...E. veterator
33’ Body shape variable, if small and shaped slightly oval then not found in coastal Texas or Louisiana...34
34 Body small and fusiform...35
34’ Body small or large, shape variable...37
35 Body nearly oval, clothed with minute setae, Great Plains above Texas...E. opaca
35’ Elytra highly punctured and glabrous...36
36 Body more fusiform, central and southern Great Plains...E. fusiformis
36’ Body less fusiform, the Sierra Nevadas to the Rocky Mountains, and the Arizona Sky Islands to British Colombia, northern Great Plains...E. extricata (in part)
37 Size medium to large, elytra usually inflated, wide, large, and rotund or occasionally flattened in E. striolata and some E. subnitens and E. madrensis, elytra only attenuate if also flattened, elytra never caudate...38
37’ Size variable but abdomen rarely inflated, if so, then size is usually small or the elytra are attenuate or caudate...41
38 Elytral striae composed of large conspicuous punctures...E. goryi
38’ Elytral striae without large punctures...39
39 Elytra flattened, always attenuate, and heavily punctate, south and central Texas...E. striolata
39’ Elytra sometimes flattened, if so then also attenuate, inconspicuous punctures present, Arizona, New Mexico, and Sonora...40
40 Pronotum more or less parallel sided...E. subnitens
40’ Pronotum evenly arcuate...E. madrensis
41 Size large sometimes medium or small in rare occasions, but always with legs long, sometimes caudate...42
41’ Size usually small, sometimes medium, if so then legs short, never caudate...71
42 Body elongate, sometimes robust, pronotum not all that distinct from elytra, profemora never dentate and never with caudate elytra, punctures simple or muricate/scabrous...43
42’ Body fairly variable, sometimes elongate, often robust, pronotum usually quite distinct from elytra, males almost always with dentate profemora, elytra sometimes caudate...48
43 Elytral punctures simple…45
43’ Elytral punctures not simple…44
44 Anterolateral angles strongly projected, elytral punctures with tiny inconspicuous setae arising from each one...E. inornata
44’ Anterolateral angles not projected or only slightly projected, elytral punctures glabrous…E. nigrina (continuation)
45 Tarsi with grey spicules in the plantar groove, often with red line running down the length of the elytra, this line never diffuses into black...E. ornatipennis
45’ Tarsi without grey spicules in the plantar groove, if a red line is present along the elytra it diffuses into black...46
46 Profemora strongly sinuate, pronotum widest slightly anterior of middle...E. hepburni
46’ Profemora simple, pronotum widest at middle...47
47 Pronotun wider than long, restricted to California...E. gigantea
47’ Pronotum as wide as long or longer than wide, widespread but not found in California...E. longicollis
48 Elytra never completely smooth (muricate, irregularly punctured, sulcate even if sulci not deep), pronotum sometimes concave, body large, robust, and elytra with carina, if carina absent and body not very robust, then anterolateral angles of the pronotum rounded off, and the pronotum widest anterior of middle...49
48’ Elytra variable, often smooth, pronotum never concave, body variable, and elytra lacking carina, if elytra sulcate then pronotum widest at middle or with acute anterolateral angles...54
49 Pronotum concave...E. suturalis
49’ Pronotum convex...50
50 Elytra with carina...E. acuta
50’ Elytra without carina...51 (E. obscura)
51 Elytra with striae...52
51’ Elytra without striae...53
52 Elytra deeply sulcate...E. obscura sulcipennis
52’ Elytra slightly sulcate...E. obscura obscura
53 Elytra with simple punctures...E. obscura glabrisulca
53’ Elytra with muricate punctures...E. obscura dispersa
54 Elytra with large glabrous costae, intervals minutely hirsute, often coated with white debris, males are caudate, females are sometimes slightly caudate, legs long...E. mirabilis
54’ Elytra variable but without costae, caudate or not...55
55 Pronotum very wide, humeral angles of elytra obsolete, never attenuate...E. grandicollis
55 Pronotum variable, if wide, then elytral apex attenuate at least, humeral angles of elytra not obsolete...56
56 Restricted to California and the Baja peninsula, never having deep sulci...57
56’ Widespread not found in California or the northern Baja peninsula, if found in California then elytra sulcate...63
57 Pronotum two times wider than the head...E. acuticauda
57’ Pronotum less then two times wider than the head...58
58 Pronotum more or less parallel sided, Mohave desert...59
58’ Pronotum not parallel sided, or if so then elytral apex with groove in between both elytra, coastal and inland California…60
59 Tibia strongly curved, profemoral spines blunt, never caudate...E. subcylindrica
59’ Tibia not strongly curved, profemoral spines acute, males caudate...E. mexicana
60 Elytral punctures minute, pronotum nearly parallel sided, although sometimes slightly arcuate, elytral apex with groove in between both elytra…E. discincta
60’ Elytral punctures not minute, or if so then pronotum wide…61
61 Pronotum larger, elytral striae less prominent…E. dentipes
61’ Pronotum smaller, elytral striae more prominent…62
62 Pronotum widest anterior of middle, luster more shiny, elytra with simple punctures, glabrous, striae very clear…E. gracilis distans
62’ Pronotum widest at middle, luster more dull, elytra with muricate punctures and conspicuous setae, striae not clearly defined…E. adumbrata
63 Elytra strongly sulcate…64
63’ Elytra not strongly sulcate…65
64 Pronotum widest anterior to middle…E. hispilabris
64’ Pronotum widest at middle…E. composita
65 Body flattened, elytra and pronotum not too distinctly separated, or elytra remain wide up until their humeral angles…E. knullorum
65’ Body usually not flat, elytra and pronotum clearly separate, if elytra remain wide up until their humeral angles, then elytra inflated…66
66 Elytra with muricate punctures…67
66’ Elytra with simple punctures…68
67 Punctures of elytra arranged in rows, elytral apex attenuate or caudate…E. tenuipes
67’ Punctures of elytra irregular, elytral apex only sometimes attenuate…E. sponsa
68 Elytra inflated and strongly convex…69 (E. spinipes)
68’ Elytra not inflated…70
69 Elytra more or less parallel sided, western Texas to Arizona…E. spinipes macrura
69’ Elytra ventricose, southern Texas…E. spinipes ventricosa
70 Male metatibia sinuate, males caudate, females strongly attenuate, strial punctures not abnormally large…E. eschscholtzii eschscholtzii
70’ Metatibia not sinuate, elytral apex only slightly attenuate, striae composed of rows of moderately sized punctures…E. gracilis gracilis
71 Elytra with conspicuous setae…72
71’ Elytra glabrous, or only with short inconspicuous setae…76
72 Size less than 12mm, elytra shiny with complex sculpturing, and covered in golden hairs, areas with sandy soils generally around the Four Corners…E. barbata
72’ Size usually small but rarely less than 12mm, elytra usually dull, sometimes shiny, never with golden hairs, usually in deserts above the Sonoran desert…73
73 Size larger, body more robust, northern Arizona and southern Utah…E. halli
73’ Size smaller, body more slender, generally around the Great Basin and the Great Sand Dunes of Colorado…74
74 Distributed only in the Great Sand Dunes National Park…E. hirtipennis
74’ Distributed generally around the Great Basin…75
75 Setae black, generally around the great basin…E. letcheri
75’ Setae brownish, in and around Utah…E. aspera
76 Elytra flat and widened, about the same width as pronotum, sides sometimes slightly rounded or with carina…77
76’ Sides of elytra rounded evenly, generally elongate or circular…81
77 Body covered with minute setae…E. tricostata
77’ Body glabrous…78
78 Elytral sculpturing rough, luster generally dull, striae vague to absent…E. neomexicana
78’ Elytra with clear striae, luster shiny…79
79 Elytra with deeply impressed striae…E. pedinoides
79’ Elytra with slightly impressed striae…80 (E. wenzeli)
80 Punctures of elytra fine but easily noticeable…E. wenzeli speculicollis
80’ Punctures of elytra extremely fine and minute…E. wenzeli wenzeli
81 Both elytra with at least three large smooth costae, southern Utah…E. parowana
81’ Both elytra without at least three large costae…82
82 Size small, elytral luster generally shiny, elytra only with conspicuous irregular punctures, never with tubercules…E. extricata (continuation)
82’ Size small to medium, luster variable although generally dull if elytra with irregular punctures, said irregular punctures also smaller, elytra with punctures in rows or irregular, or with tubercules or papillae…83
83 Elytra generally inflated, if not, then elytra more or less parallel sided, usually tuberculate, Pacific Northwest…E. humeralis
83’ Elytra inflated or not, but if with tubercules then elytra not inflated and not parallel sided, if without tubercules then not found in the Pacific Northwest, or if in the Pacific Northwest then pronotum not clearly widest in front of middle…84
84 Elytra with papillae, pronotum wide…E. papillosa
84’ Elytra without papillae…85
85 Elytra with large tubercules…86
85’ Elytra without large tubercules…87
86 Pronotum more or less arcuate and wider than long…E. granulata
86’ Pronotum more or less parallel sided and longer than wide…E. subtuberculata
87 Size small, pronotum evenly arcuate, lateral edges angular instead of rounded, punctures minute…E. arcuata
87’ Size variable, pronotum variable, but if arcuate, then lateral edges rounded…88
88 Luster shiny, elytral punctures large and in rows, outer protibial spur clearly larger than inner protibial spur…E. debilis
88’ Luster variable but usually not too shiny, punctures variable but rarely large, if protibial spurs disproportionate in size, then elytra with small punctures or tubercules…89
89 Longer protibial spur extending to almost to the third tarsomere…90 (E. rileyi)
89’ Longer protibial spur extending only to apex of the first tarsomere…91
90 Elytra shiny with prominent striae…E. rileyi reducta
90’ Elytra dull without very prominent striae…E. rileyi rileyi
91 “…longer protibial spur evenly tapering to a point from base to apex”…E. carbonaria (see Thomas 2012 for subspecies key)
91’ “…longer protibial spur parallel sided in basal half then tapering to a point at apex”…92
92 Elytral punctures irregular, San Francisco region…E. quadricollis
92’ Elytral punctures organized in rows, southeast Arizona…93 (E. anthracina)
93 Size larger, elytral punctures less fine…E. anthracina anthracina
93’ Size smaller, elytral punctures more fine…E. anthracina lustrans

Some more slight improvements, mainly with the nominate subgenus. More information in V1.0: https://www.inaturalist.org/journal/eleodesthermopolis/87075-v1-0-a-key-to-the-eleodes-species-of-the-united-states-and-canada-outdated

1 Mesofemora and metafemora dentate or subdentate...2
1’ Mesofemora and metafemora never dentate...4
2 Elytral punctures strongly muricate...E. moesta
2’ Elytral punctures simple or slightly muricate...3
3 Pronotum widest anterior of middle, femoral spines large...E. armata
3’ Pronotum widest at middle, femoral spines small to medium sized...E. femorata
4 Body small, pronotum generally cordate and constricted at base, elytra apex not attenuate or caudate, roughly sculptured, distributed across beaches, forests, and mountains...subgenus Blapylis
4’ Body small or large, pronotum usually not cordate although often slightly constricted at base, elytral apex attenuate, caudate or neither, roughly sculptured or not, widespread across all environments...5
5 Legs long with unproportionately small body, robust or not, body often flattened if not robust...6
5’ Legs long or short but with body fairly proportionate, only rarely flattened...22
6 Body generally slender and flattened, pronotal and elytral sculpturing simple (except in E. nigrina)...7
6’ Body, generally robust, never flattened, pronotal and elytral sculpturing complex...18
7 Elytral sculpturing muricate or scabrous...E. nigrina (in part)
7’ Elytral sculpturing simple...8
8 Range only in Inyo White Mountains...9
8’ Range widespread...10
9 Profemora with large tooth, anterolateral angles blunt but projected...E. aalbui
9’ Profemora only sinuate, anterolateral angles slightly projected...E. microps
10 Range near Big Bend National Park and the Guadalupe Mountains...11
10’ Range in the Southwest United States excluding Texas and the Guadalupe Mountains...13
11 Range in the Guadalupe Mountains...E. guadalupensis
11’ Range in Big Bend National Park...12
12 Mentum with finger-like process, pronotum lacking projected anterolateral angles, widest at middle...E. labialis
12’ Mentum without finger-like process, pronotum with anterolateral angles...E. easterlai
13 Range in the Mohave Desert of California, pronotum usually evenly arcuate...E. californica
13’ Range in Arizona, Utah, and Sonora, pronotum rarely evenly arcuate...14
14 Range in the Sonoran desert or the most western portion of the Arizona-Utah border...15
14’ Range in the Sky Islands or the Colorado Plateau...16
15 Anterolateral angles strongly projected, caves by the most western point of the Arizona-Utah border…E. wynnei
15’ Anterolateral angles not strongly projected, the Sonoran desert…E. delicata (E. nevadensis)
16 Body elongate, northern Arizona and southern Utah...17
16’ Body not elongate, Sky Islands in southeast Arizona...E. dissimilis
17 Strial punctures larger than punctures of intervals, restricted to the Grand Canyon...E. leptoscelis
17’ Strial punctures subequal to punctures of intervals, northern Arizona and southern Utah...E. wheeleri
18 Large tubercles present on Elytra...19
18’ Elytra without large tubercules...20
19 Range in Sierra Nevada region...E. granosa
19’ Range near the Four Corners...E. leechi
20 Pronotum evenly tuberculate, range in Oregon...E. spoliata
20’ Pronotum punctate, range widespread...21
21 Antennas robust, body generally more robust...E. hirsuta
21’ Antennas thin, body generally more slender...E. pilosa
22 Size small or sometimes medium, covered in long setae, restricted to coastal California and the Baja peninsula, and the Sonoran desert...23
22’ Size small or large, usually glabrous, if with conspicuous setae then not found in coastal California, nor in the Baja peninsula or the Sonoran desert...28
23 Males with dentate profemora and elytra caudate, Sonoran desert...E. tribulus
23’ Males nor females ever caudate or attenuate, coastal California and the Baja peninsula...24
24 Third antennomere shortened, body smaller and more slender...E. littoralis
24’ Third antennomere not shorted, body larger...25
25 Body larger, pronotum with constriction at base, if missing constriction then setae more dense...26
25’ Body smaller, pronotum lacking constriction at base, setae less dense...27
26 Setae orange, California and northern Baja peninsula...E. osculans
26’ Setae black or grey, California and northern Baja peninsula...E. ursus
27 Setae black, California and northern Baja peninsula...E. nigropilosa
27’ Setae yellow, Baja peninsula...E. subdeplanata
28 Elytra caudate at least in males and strongly muricate, near Tamaulipas if not caudate, size usually large...29
28’ Elytra caudate or not, but if caudate and muricately punctured then elytra only slightly muricate, elytra can be strongly muricate if not caudate and not near Tamaulipas, size large or small...31
29 Only males caudate with profemora dentate, Tamaulipas...E. fiski
29’ Both males and females caudate with mutic profemora, Four Corners and Sierra Nevada region...30
30 Elytra usually glabrous, rarely with setae, Four Corners...E. caudifera
30’ Elytra always with long setae, Sierra Nevada region...E. longipilosa
31 Elytral sculpture very rough, elytra always attenuate but never caudate, restricted to California...32
31’ Elytral sculpture variable but if rough then elytra never attenuate, widespread...33
32 Luster shiny and elytral apex acutely attenuate...E. marginata
32’ Luster dull and elytral apex blunt yet still attenuate...E. scabricula (E. acutangula)
33 Body oval shaped, coated in minute setae, coastal Texas and Louisiana...E. veterator
33’ Body shape variable, if small and shaped slightly oval then not found in coastal Texas or Louisiana...34
34 Body small and fusiform...35
34’ Body small or large, shape variable...37
35 Body nearly oval, clothed with minute setae, giving body a grey appearance, Great Plains of northern Texas to Canada...E. opaca
35’ Elytra highly punctured and glabrous...36
36 Body more fusiform, central and southern Great Plains...E. fusiformis
36’ Body less fusiform, the Sierra Nevadas to the Rocky Mountains, and the Arizona Sky Islands to British Colombia, northern Great Plains...E. extricata (in part)
37 Size medium to large, elytra usually inflated, wide, large, and rotund or sometimes flattened, especially in E. striolata, punctures either large, or appearing absent, although if elytra are not inflated, and attenuate, then punctures may be numerous and conspicuous...38
37’ Size variable but abdomen rarely inflated, if so, then punctures are small but conspicuous...41
38 Elytral striae composed of large conspicuous punctures...E. goryi
38’ Elytral striae without large punctures...39
39 Elytra usually flattened, always attenuate, and heavily punctate, luster shiny, south and central Texas...E. striolata
39’ Elytra sometimes flattened, inconspicuous punctures present, luster usually dull, Arizona, New Mexico, and Sonora...40
40 Pronotum more or less parallel sided, anterolateral angles almost always projected outwards...E. subnitens
40’ Pronotum evenly arcuate, anterolateral angles only rarely projected outwards...E. madrensis
41 Size large sometimes medium or small in rare occasions, but almost always with legs long, sometimes caudate...42
41’ Size usually small, sometimes medium, if so then legs almost always short, never caudate...71
42 Body elongate, sometimes robust, pronotum not all that distinct from elytra, profemora never dentate and never with caudate elytra, punctures simple or muricate/scabrous...43
42’ Body fairly variable, sometimes elongate, often robust, pronotum usually quite distinct from elytra, males almost always with dentate profemora, elytra sometimes caudate...48
43 Elytral punctures simple…45
43’ Elytral punctures not simple…44
44 Anterolateral angles strongly projected, elytral punctures with tiny inconspicuous setae arising from each one, size usually not small...E. inornata
44’ Anterolateral angles not projected or only slightly projected, elytral punctures glabrous, size smaller, sometimes quite small…E. nigrina (continuation)
45 Elytra with red line running down the length of the elytra, this line never diffuses into black...E. ornatipennis
45’ Elytra entirely black, or if a red line is present along the elytra, it diffuses into black...46
46 Profemora strongly sinuate, pronotum widest slightly anterior of middle...E. hepburni
46’ Profemora simple, pronotum widest at middle...47
47 Pronotun wider than long, restricted to California...E. gigantea
47’ Pronotum as wide as long or longer than wide, widespread but not found in California...E. longicollis
48 Elytra never completely smooth (muricate, irregularly punctured, sulcate even if sulci not deep), pronotum sometimes concave, body large, robust, and elytra with carina, if carina absent and body not very robust, then anterolateral angles of the pronotum rounded off, and the pronotum widest anterior of middle...49
48’ Elytra variable, often smooth, pronotum never concave, body variable, and elytra lacking carina, if elytra sulcate then pronotum widest at middle or with acute anterolateral angles...54
49 Pronotum concave...E. suturalis
49’ Pronotum convex...50
50 Elytra with carina...E. acuta
50’ Elytra without carina...51 (E. obscura)
51 Elytra sulcate...52
51’ Elytra not sulcate...53
52 Elytra deeply sulcate, west of the Great Plains...E. obscura sulcipennis
52’ Elytra slightly sulcate, Great Plains...E. obscura obscura
53 Elytra with simple punctures, western Texas...E. obscura glabrisulca
53’ Elytra with muricate punctures, Four Corners...E. obscura dispersa
54 Elytra with large glabrous costae, intervals minutely hirsute, often coated with white debris, males are caudate, females are sometimes slightly caudate, legs long...E. mirabilis
54’ Elytra variable but without costae, caudate or not...55
55 Pronotum very wide, humeral angles of elytra obsolete, never attenuate...E. grandicollis
55 Pronotum variable, if wide, then elytral apex attenuate at least, humeral angles of elytra not obsolete...56
56 Restricted to California and the Baja peninsula, never having deep sulci...57
56’ Widespread not found in California or the northern Baja peninsula, if found in California then elytra sulcate...63
57 Pronotum two times wider than the head...E. acuticauda
57’ Pronotum less then two times wider than the head...58
58 Pronotum more or less parallel sided, Mohave desert...59
58’ Pronotum not parallel sided, or if so then elytral apex with groove in between both elytra, coastal and inland California…60
59 Tibia strongly curved, profemoral spines blunt, never caudate...E. subcylindrica
59’ Tibia not strongly curved, profemoral spines acute, males caudate...E. mexicana
60 Elytral punctures minute, pronotum nearly parallel sided, although sometimes slightly arcuate, elytral apex with groove in between both elytra…E. discincta
60’ Elytral punctures not minute, or if so then pronotum wide…61
61 Pronotum larger, elytral striae less prominent…E. dentipes
61’ Pronotum smaller, elytral striae more prominent…62
62 Pronotum widest anterior of middle, luster more shiny, elytra with simple punctures, glabrous, striae very clear…E. gracilis distans
62’ Pronotum widest at middle, luster more dull, elytra with muricate punctures and conspicuous setae, striae not clearly defined…E. adumbrata
63 Elytra strongly sulcate, at least on elytral apex…64
63’ Elytra not strongly sulcate…65
64 Pronotum widest anterior to middle…E. hispilabris
64’ Pronotum widest at middle…E. composita
65 Body flattened, elytra and pronotum not too distinctly separated, or if so then elytra remain wide up until their humeral angles…E. knullorum
65’ Body usually not flat, elytra and pronotum clearly separate, if elytra remain wide up until their humeral angles, then elytra inflated…66
66 Elytra with muricate punctures…67
66’ Elytra with simple punctures…68
67 Punctures of elytra arranged in rows and fairly muricate, elytral apex attenuate or caudate, El Paso region…E. tenuipes
67’ Punctures of elytra irregular and strongly muricate, elytral apex only sometimes attenuate, generally around the Four Corners and western Texas…E. sponsa
68 Hind angles of pronotum appearing rounded, size large, elytra often inflated and strongly convex, or fairly parallel sided…69 (E. spinipes)
68’ Hind angles of pronotum not rounded or only slightly rounded, size medium to large, elytra never inflated, but often parallel sided…70
69 Elytra more or less parallel sided, west of the Pecos River…E. spinipes macrura
69’ Elytra ventricose, east of the Pecos River…E. spinipes ventricosa
70 Anterolateral angles of pronotum always facing straight forward, never projecting outwards, male metatibia sinuate, males caudate, females strongly attenuate, strial punctures inconspicuous…E. eschscholtzii eschscholtzii
70’ Anterolateral angles of pronotum always projecting outwards at least a little, metatibia not abnormally sinuate, elytral apex only slightly attenuate, striae composed of rows of conspicuous punctures…E. gracilis gracilis
71 Elytra with conspicuous setae…72
71’ Elytra glabrous, or only with short inconspicuous setae…76
72 Size less than 12mm, elytra shiny with complex sculpturing, and covered in golden hairs, areas with sandy soils generally around the Four Corners…E. barbata
72’ Size usually small but rarely less than 12mm, elytra usually dull, sometimes shiny, never with golden hairs, usually in deserts above the Sonoran desert…73
73 Size larger, body more robust, northern Arizona and southern Utah…E. halli
73’ Size smaller, body more slender, generally around the Great Basin and the Great Sand Dunes of Colorado…74
74 Distributed only in the Great Sand Dunes National Park…E. hirtipennis
74’ Distributed generally around the Great Basin…75
75 Setae black, generally around the great basin…E. letcheri
75’ Setae brownish, in and around Utah…E. aspera
76 Elytra flat and widened, about the same width as pronotum, sides sometimes slightly rounded or with carina…77
76’ Sides of elytra rounded evenly, generally elongate or circular…81
77 Body covered with minute setae, usually appearing grey in color…E. tricostata
77’ Body glabrous…78
78 Elytral sculpturing rough, striae vague to absent, luster generally dull…E. neomexicana
78’ Elytra with clear striae, luster shiny…79
79 Elytra with deeply impressed striae…E. pedinoides
79’ Elytra with slightly impressed striae…80 (E. wenzeli)
80 Punctures of elytra fine but easily noticeable…E. wenzeli speculicollis
80’ Punctures of elytra extremely fine and minute…E. wenzeli wenzeli
81 Both elytra with at least three large smooth costae, legs often dark red, southern Utah…E. parowana
81’ Both elytra without at least three large costae…82
82 Size small, elytral luster generally shiny, elytra only with conspicuous irregular punctures, never with tubercules…E. extricata (continuation)
82’ Size small to medium, luster variable although generally dull if elytra with irregular punctures, said irregular punctures also smaller, elytra with punctures in rows or irregular, or with tubercules or papillae…83
83 Elytra generally inflated, if not, then elytra more or less parallel sided, usually tuberculate, Pacific Northwest…E. humeralis
83’ Elytra inflated or not, but if with tubercules then elytra not inflated and not parallel sided, if without tubercules then not found in the Pacific Northwest, or if in the Pacific Northwest then pronotum not clearly widest in front of middle…84
84 Elytra with papillae, pronotum wide…E. papillosa
84’ Elytra without papillae…85
85 Elytra with large tubercules…86
85’ Elytra without large tubercules…87
86 Pronotum more or less arcuate and wider than long…E. granulata
86’ Pronotum more or less parallel sided and longer than wide…E. subtuberculata
87 Size small, pronotum evenly arcuate, lateral edges angular instead of rounded, punctures minute…E. arcuata
87’ Size variable, pronotum variable, but if arcuate, then lateral edges rounded…88
88 Luster shiny, elytral punctures large and in rows, outer protibial spur clearly larger than inner protibial spur…E. debilis
88’ Luster variable but usually not too shiny, punctures variable but rarely large, if protibial spurs disproportionate in size, then elytra with small punctures or tubercules…89
89 Longer protibial spur extending to almost to the third tarsomere…90 (E. rileyi)
89’ Longer protibial spur extending only to apex of the first tarsomere…91
90 Elytra shiny with prominent striae…E. rileyi reducta
90’ Elytra dull without very prominent striae…E. rileyi rileyi
91 “…longer protibial spur evenly tapering to a point from base to apex”…E. carbonaria (see Thomas 2012 for subspecies key)
91’ “…longer protibial spur parallel sided in basal half then tapering to a point at apex”…92
92 Elytral punctures irregular, San Francisco region…E. quadricollis
92’ Elytral punctures organized in rows, southeast Arizona…93 (E. anthracina)
93 Size larger, elytral punctures less fine…E. anthracina anthracina
93’ Size smaller, elytral punctures more fine…E. anthracina lustrans

I just realized that I’ve been using the wrong “your” every time someone has thanked me, so, pretend I’ve been saying you’re welcome!

More miscellaneous improvements, such as better/more specific phrasing, and more inclusion for locations and specimens. More info in V1.0: https://www.inaturalist.org/journal/eleodesthermopolis/87075-v1-0-a-key-to-the-eleodes-species-of-the-united-states-and-canada-outdated

1 Mesofemora and metafemora dentate or subdentate...2
1’ Mesofemora and metafemora never dentate...4
2 Elytral punctures strongly muricate...E. moesta
2’ Elytral punctures simple or slightly muricate...3
3 Pronotum widest anterior of middle, femoral spines large...E. armata
3’ Pronotum widest at middle, femoral spines small to medium sized...E. femorata
4 Body small, pronotum generally cordate and constricted at base, elytra apex not attenuate or caudate, roughly sculptured, never sulcate, sometimes with short setae, usually distributed across beaches, forests, and mountains, rarely in arid regions...subgenus Blapylis
4’ Body small or large, pronotum usually not cordate although often slightly constricted at base, elytral apex attenuate, caudate or neither, roughly sculptured or not, sulcate or not, with setae or not, widespread across all environments...5
5 Legs long with unproportionately small body, robust or not, body often flattened if not robust, never sulcate, if legs not abnormally long, then body elongate and flattened...6
5’ Legs long or short but with body fairly proportionate, only rarely flattened, sulcate or not, if legs fairly long, then not with conspicuous setae, or a small, elongate, and flattened body...22
6 Body generally slender and flattened, pronotal and elytral sculpturing simple (except in E. nigrina), never with conspicuous setae...7
6’ Body, generally robust, never flattened, pronotal and elytral sculpturing complex, usually with conspicuous setae...18
7 Elytral sculpturing muricate or scabrous, southern New Mexico to Canada, Sierra Nevada Mountains to Rocky Mountains...E. nigrina (in part)
7’ Elytral sculpturing simple, always below the northernmost edge of Colorado’s border...8
8 Range only in Inyo White Mountains...9
8’ Range widespread...10
9 Profemora with blunt tooth, anterolateral angles of pronotum blunt but projected, legs shorter...E. aalbui
9’ Profemora only sinuate, anterolateral angles of pronotum slightly projected, legs longer...E. microps
10 Range near Big Bend National Park and the Guadalupe Mountains...11
10’ Range in the Southwest United States excluding Texas and the Guadalupe Mountains...13
11 Range in the Guadalupe Mountains...E. guadalupensis
11’ Range near Big Bend National Park...12
12 Mentum with finger-like process, pronotum lacking projected anterolateral angles, widest at middle, near Rio Grande river...E. labialis
12’ Mentum without finger-like process, pronotum with slightly projected anterolateral angles, Big Bend National Park...E. easterlai
13 Range in the Mohave Desert of California, pronotum usually evenly arcuate...E. californica
13’ Range in Arizona, Utah, and Sonora, pronotum rarely evenly arcuate...14
14 Range in the Sonoran desert or the most western portion of the Arizona-Utah border...15
14’ Range in the Sky Islands or the Colorado Plateau...16
15 Anterolateral angles strongly projected, caves by the most western point of the Arizona-Utah border…E. wynnei
15’ Anterolateral angles not strongly projected, the Sonoran desert…E. delicata (E. nevadensis)
16 Body elongate, northern Arizona and southern Utah...17
16’ Body not elongate, Sky Islands in southeast Arizona...E. dissimilis
17 Strial punctures larger than punctures of intervals, restricted to the Grand Canyon...E. leptoscelis
17’ Strial punctures subequal to punctures of intervals, northern Arizona and southern Utah...E. wheeleri
18 Large tubercles present on Elytra...19
18’ Elytra without large tubercules...20
19 Range in Sierra Nevada region...E. granosa
19’ Range near the Four Corners...E. leechi
20 Pronotum evenly tuberculate, range in Oregon...E. spoliata
20’ Pronotum punctate, range widespread...21
21 Antennas robust, body generally more robust...E. hirsuta
21’ Antennas thin, body generally more slender...E. pilosa
22 Size small or sometimes medium, covered in long setae, restricted to coastal and sometimes inland California, and the Baja peninsula, or rarely in the direction of and in Reno, or the Sonoran desert...23
22’ Size small or large, usually glabrous, if with conspicuous setae then not found in coastal California, nor in the Baja peninsula, or the Sonoran desert, and if found near Reno, Nevada, then third antennomere not shortened...28
23 Males with dentate profemora and elytra caudate, Sonoran desert...E. tribulus
23’ Males nor females ever caudate or attenuate, coastal California and the Baja peninsula...24
24 Third antennomere shortened, body smaller and more slender, pill shaped, coastal California and towards and into Reno, Nevada...E. littoralis
24’ Third antennomere not shorted, body larger, California...25
25 Body larger, pronotum with constriction at base, if missing constriction then setae more dense...26
25’ Body smaller, pronotum lacking constriction at base, setae less dense...27
26 Setae orange, California and northern Baja peninsula...E. osculans
26’ Setae black or grey, California and northern Baja peninsula...E. ursus
27 Setae black, California and northern Baja peninsula...E. nigropilosa
27’ Setae yellow, Baja peninsula...E. subdeplanata
28 Elytra caudate at least in males and strongly muricate, near Tamaulipas if not caudate, size usually large...29
28’ Elytra caudate or not, but if caudate and muricately punctured then elytra only slightly muricate, elytra can be strongly muricate if not caudate and not near Tamaulipas, size large or small...31
29 Only males caudate with profemora dentate, Tamaulipas...E. fiski
29’ Both males and females caudate with mutic profemora, Four Corners and Sierra Nevada region...30
30 Elytra usually glabrous, rarely with setae, Four Corners...E. caudifera
30’ Elytra always with long setae, Sierra Nevada region...E. longipilosa
31 Elytral sculpture very rough, elytra always attenuate but never caudate, pronotum wide, restricted to California, or slightly into Nevada and Oregon...32
31’ Elytral sculpture variable but if rough then elytra never attenuate, widespread...33
32 Luster shiny and elytral apex acutely attenuate...E. marginata
32’ Luster dull and elytral apex blunt yet still attenuate...E. scabricula (E. acutangula)
33 Body oval shaped, coated in minute setae, coastal Texas and Louisiana...E. veterator
33’ Body shape variable, if small and shaped slightly oval then not found in coastal Texas or Louisiana...34
34 Body small and fusiform...35
34’ Body small or large, shape variable...37
35 Body nearly oval, clothed with minute setae, giving body a grey appearance, Great Plains of northern Texas to Canada...E. opaca
35’ Elytra highly punctured and glabrous...36
36 Body more fusiform, central and southern Great Plains...E. fusiformis
36’ Body less fusiform, the Sierra Nevadas to the Rocky Mountains, and the Arizona Sky Islands to British Colombia, northern Great Plains...E. extricata (in part)
37 Size medium to large, elytra usually inflated, wide, and large or sometimes flattened, especially in E. striolata, punctures either large, or appearing absent, although if elytra are not inflated, and attenuate, then punctures may be numerous and conspicuous, never sulcate...38
37’ Size variable but abdomen rarely inflated, if so, then punctures are small but conspicuous, sulcate or not...41
38 Elytral striae composed of large conspicuous punctures...E. goryi
38’ Elytral striae without large punctures...39
39 Elytra usually flattened, always attenuate, and heavily punctate, luster shiny, south and central Texas...E. striolata
39’ Elytra sometimes flattened, inconspicuous punctures present, luster usually dull, Arizona, New Mexico, and Sonora...40
40 Pronotum more or less parallel sided, anterolateral angles almost always projected outwards...E. subnitens
40’ Pronotum evenly arcuate, anterolateral angles only rarely projected outwards...E. madrensis
41 Size large sometimes medium or small in rare occasions, but almost always with legs long, sometimes caudate...42
41’ Size usually small, sometimes medium, if so then legs almost always short, never caudate...71
42 Body elongate, sometimes robust, pronotum not all that distinct from elytra, profemora never dentate and never with caudate elytra, punctures simple or muricate/scabrous, never sulcate...43
42’ Body fairly variable, sometimes elongate, often robust, pronotum usually quite distinct from elytra, males almost always with dentate profemora, elytra sometimes caudate, sulcate or not...48
43 Elytral punctures simple, anterolateral angles never very projected, body rarely flattened, but if so, then usually near the Sky Islands of southeast Arizona…45
43’ Elytral punctures not simple, anterolateral angles of pronotum projected, or body somewhat flattened and small, never in the Sky Islands…44
44 Anterolateral angles strongly projected, elytral punctures with tiny inconspicuous setae arising from each one, size usually not small...E. inornata
44’ Anterolateral angles not projected or only slightly projected, elytral punctures glabrous, size smaller, sometimes quite small…E. nigrina (continuation)
45 Elytra with red line running down the length of the elytra, this line never diffuses into black...E. ornatipennis
45’ Elytra entirely black, or if a red line is present along the elytra, it diffuses into black...46
46 Profemora strongly sinuate, pronotum widest slightly anterior of middle...E. hepburni
46’ Profemora simple, pronotum widest at middle...47
47 Prosternum horizontal, not projecting downwards, restricted to California...E. gigantea
47’ Prosternum projecting downwards, widespread but not found in California...E. longicollis
48 Elytra never completely smooth (muricate, irregularly punctured, sulcate even if sulci not deep), pronotum sometimes concave, body large, robust, and elytra with carina, if carina absent and body not very robust, then anterolateral angles of the pronotum rounded off, and the pronotum widest anterior of middle...49
48’ Elytra variable, often smooth, pronotum never concave, body variable, and elytra lacking carina, if elytra sulcate, or irregularly punctured, then pronotum widest at middle or with acute anterolateral angles...54
49 Pronotum concave...E. suturalis
49’ Pronotum convex...50
50 Elytra with carina...E. acuta
50’ Elytra without carina...51 (E. obscura)
51 Elytra sulcate...52
51’ Elytra not sulcate...53
52 Elytra deeply sulcate, west of the Great Plains...E. obscura sulcipennis
52’ Elytra slightly sulcate, Great Plains...E. obscura obscura
53 Elytra with simple punctures, western Texas...E. obscura glabrisulca
53’ Elytra with muricate punctures, Four Corners...E. obscura dispersa
54 Elytra with large glabrous costae, intervals minutely hirsute, often coated with white debris, males are caudate, females are sometimes slightly caudate, legs long...E. mirabilis
54’ Elytra variable but without costae, caudate or not...55
55 Pronotum very wide, humeral angles of elytra obsolete, never attenuate...E. grandicollis
55 Pronotum variable, if wide, then elytral apex attenuate at least, humeral angles of elytra not obsolete...56
56 Restricted to California and the Baja peninsula, never having deep sulci...57
56’ Widespread not found in California or the northern Baja peninsula, if found in California then elytra sulcate...63
57 Pronotum two times wider than the head...E. acuticauda
57’ Pronotum less then two times wider than the head...58
58 Pronotum more or less parallel sided, Mohave desert...59
58’ Pronotum not parallel sided, or if so then elytral apex with groove in between both elytra, coastal and inland California…60
59 Tibia strongly curved, profemoral spines blunt, never caudate...E. subcylindrica
59’ Tibia not strongly curved, profemoral spines acute, males caudate...E. mexicana
60 Elytral punctures minute, pronotum nearly parallel sided, although sometimes slightly arcuate, elytral apex with groove in between both elytra…E. discincta
60’ Elytral punctures not minute, or if so then pronotum wide…61
61 Pronotum larger, elytral striae less prominent…E. dentipes
61’ Pronotum smaller, elytral striae more prominent…62
62 Pronotum widest anterior of middle, luster more shiny, elytra with simple punctures, glabrous, striae very clear…E. gracilis distans
62’ Pronotum widest at middle, luster more dull, elytra with muricate punctures and conspicuous setae, striae not clearly defined…E. adumbrata
63 Elytra strongly sulcate, at least on elytral apex…64
63’ Elytra not strongly sulcate…65
64 Pronotum widest anterior to middle…E. hispilabris
64’ Pronotum widest at middle…E. composita
65 Body flattened, elytra and pronotum not too distinctly separated, or if so then elytra remain wide up until their humeral angles…E. knullorum
65’ Body usually not flat, elytra and pronotum clearly separate, if elytra remain wide up until their humeral angles, then elytra inflated…66
66 Elytra with muricate punctures…67
66’ Elytra with simple punctures…68
67 Punctures of elytra arranged in rows and fairly muricate, elytral apex always caudate, even if short, El Paso region…E. tenuipes
67’ Punctures of elytra irregular and strongly muricate, elytral apex only sometimes attenuate, generally around the Four Corners and western Texas…E. sponsa
68 Hind angles of pronotum appearing rounded, size large, elytra often inflated and strongly convex, or fairly parallel sided…69 (E. spinipes)
68’ Hind angles of pronotum not rounded or only slightly rounded, size medium to large, elytra never inflated, but often parallel sided…70
69 Elytra more or less parallel sided, west of the Pecos River…E. spinipes macrura
69’ Elytra ventricose, east of the Pecos River…E. spinipes ventricosa
70 Anterolateral angles of pronotum always facing straight forward, never projecting outwards, male metatibia sinuate, males caudate, females strongly attenuate, strial punctures inconspicuous…E. eschscholtzii eschscholtzii
70’ Anterolateral angles of pronotum always projecting outwards at least a little, metatibia not abnormally sinuate, elytral apex only slightly attenuate, striae composed of rows of conspicuous punctures…E. gracilis gracilis
71 Elytra with conspicuous setae…72
71’ Elytra glabrous, or only with short inconspicuous setae…76
72 Size less than 12mm, elytra shiny with complex sculpturing, and covered in golden hairs, areas with sandy soils generally around the Four Corners…E. barbata
72’ Size usually small but rarely less than 12mm, elytra usually dull, sometimes shiny, never with golden hairs, usually in deserts above the Sonoran desert…73
73 Size larger, body more robust, northern Arizona and southern Utah…E. halli
73’ Size smaller, body more slender, generally around the Great Basin and the Great Sand Dunes of Colorado…74
74 Distributed only in the Great Sand Dunes National Park…E. hirtipennis
74’ Distributed generally around the Great Basin…75
75 Setae black, generally around the great basin…E. letcheri
75’ Setae brownish, in and around Utah…E. aspera
76 Elytra flat and widened, about the same width as pronotum, sides sometimes slightly rounded or with carina…77
76’ Sides of elytra rounded evenly, generally elongate or circular…81
77 Body covered with minute setae, usually appearing grey in color…E. tricostata
77’ Body glabrous…78
78 Elytral sculpturing rough, striae vague to absent, luster generally dull…E. neomexicana
78’ Elytra with clear striae, luster shiny…79
79 Elytra with deeply impressed striae…E. pedinoides
79’ Elytra with slightly impressed striae…80 (E. wenzeli)
80 Punctures of elytra fine but easily noticeable…E. wenzeli speculicollis
80’ Punctures of elytra extremely fine and minute…E. wenzeli wenzeli
81 Both elytra with at least three large smooth costae, legs often dark red, southern Utah…E. parowana
81’ Both elytra without at least three large costae…82
82 Size small, elytral luster generally shiny, elytra only with conspicuous irregular punctures, never with tubercules…E. extricata (continuation)
82’ Size small to medium, luster variable although generally dull if elytra with irregular punctures, said irregular punctures also smaller, elytra with punctures in rows or irregular, or with tubercules or papillae…83
83 Elytra generally inflated, if not, then elytra more or less parallel sided, usually tuberculate, Pacific Northwest…E. humeralis
83’ Elytra inflated or not, but if with tubercules then elytra not inflated and not parallel sided, if without tubercules then not found in the Pacific Northwest, or if in the Pacific Northwest then pronotum not clearly widest in front of middle…84
84 Elytra with papillae, pronotum wide…E. papillosa
84’ Elytra without papillae…85
85 Elytra with large tubercules…86
85’ Elytra without large tubercules…87
86 Pronotum more or less arcuate and wider than long…E. granulata
86’ Pronotum more or less parallel sided and longer than wide…E. subtuberculata
87 Size small, pronotum evenly arcuate, lateral edges angular instead of rounded, punctures minute…E. arcuata
87’ Size variable, pronotum variable, but if arcuate, then lateral edges rounded…88
88 Luster shiny, elytral punctures large and in rows, outer protibial spur clearly larger than inner protibial spur…E. debilis
88’ Luster variable but usually not too shiny, punctures variable but rarely large, if protibial spurs disproportionate in size, then elytra with small punctures or tubercules…89
89 Longer protibial spur extending to almost to the third tarsomere…90 (E. rileyi)
89’ Longer protibial spur extending only to apex of the first tarsomere…91
90 Elytra shiny with prominent striae…E. rileyi reducta
90’ Elytra dull without very prominent striae…E. rileyi rileyi
91 “…longer protibial spur evenly tapering to a point from base to apex”…E. carbonaria (see Thomas 2012 for subspecies key)
91’ “…longer protibial spur parallel sided in basal half then tapering to a point at apex”…92
92 Elytral punctures irregular, San Francisco region…E. quadricollis
92’ Elytral punctures organized in rows, southeast Arizona…93 (E. anthracina)
93 Size larger, elytral punctures less fine…E. anthracina anthracina
93’ Size smaller, elytral punctures more fine…E. anthracina lustrans

Turns out I accidentally removed E. corvina a while back, so this new version is mainly for its readdition. More info on my profile: https://www.inaturalist.org/people/6449260

1 Mesofemora and metafemora dentate or subdentate...2
1’ Mesofemora and metafemora never dentate...4
2 Elytral punctures strongly muricate...E. moesta
2’ Elytral punctures simple or slightly muricate...3
3 Pronotum widest anterior of middle, femoral spines large...E. armata
3’ Pronotum widest at middle, femoral spines small to medium sized...E. femorata
4 Body small, pronotum generally cordate and constricted at base, elytra apex not attenuate or caudate, roughly sculptured, never sulcate, sometimes with short setae, usually distributed across beaches, forests, and mountains, rarely in arid regions...subgenus Blapylis
4’ Body small or large, pronotum usually not cordate although often slightly constricted at base, elytral apex attenuate, caudate or neither, roughly sculptured or not, sulcate or not, with setae or not, widespread across all environments...5
5 Legs long with unproportionately small body, robust or not, body often flattened if not robust, never sulcate, if legs not abnormally long, then body elongate and flattened...6
5’ Legs long or short but with body fairly proportionate, only rarely flattened, sulcate or not, if legs fairly long, then not with conspicuous setae, or a small, elongate, and flattened body...22
6 Body generally slender and flattened, pronotal and elytral sculpturing simple (except in E. nigrina), never with conspicuous setae...7
6’ Body, generally robust, never flattened, pronotal and elytral sculpturing complex, usually with conspicuous setae...18
7 Elytral sculpturing muricate or scabrous, southern New Mexico to Canada, Sierra Nevada Mountains to Rocky Mountains...E. nigrina (in part)
7’ Elytral sculpturing simple, always below the northernmost edge of Colorado’s border...8
8 Range only in Inyo White Mountains...9
8’ Range widespread...10
9 Profemora with blunt tooth, anterolateral angles of pronotum blunt but projected, legs shorter...E. aalbui
9’ Profemora only sinuate, anterolateral angles of pronotum slightly projected, legs longer...E. microps
10 Range near Big Bend National Park and the Guadalupe Mountains...11
10’ Range in the Southwest United States excluding Texas and the Guadalupe Mountains...13
11 Range in the Guadalupe Mountains...E. guadalupensis
11’ Range near Big Bend National Park...12
12 Mentum with finger-like process, pronotum lacking projected anterolateral angles, widest at middle, near Rio Grande river...E. labialis
12’ Mentum without finger-like process, pronotum with slightly projected anterolateral angles, Big Bend National Park...E. easterlai
13 Range in the Mohave Desert of California, pronotum usually evenly arcuate...E. californica
13’ Range in Arizona, Utah, and Sonora, pronotum rarely evenly arcuate...14
14 Range in the Sonoran Desert or the most western portion of the Arizona-Utah border...15
14’ Range in the Sky Islands or the Colorado Plateau...16
15 Anterolateral angles strongly projected, caves by the most western point of the Arizona-Utah border…E. wynnei
15’ Anterolateral angles not strongly projected, the Sonoran Desert…E. delicata (E. nevadensis)
16 Body elongate, northern Arizona and southern Utah...17
16’ Body not elongate, Sky Islands in southeast Arizona...E. dissimilis
17 Strial punctures larger than punctures of intervals, restricted to the Grand Canyon...E. leptoscelis
17’ Strial punctures subequal to punctures of intervals, northern Arizona and southern Utah...E. wheeleri
18 Large tubercles present on Elytra...19
18’ Elytra without large tubercules...20
19 Range in Sierra Nevada region...E. granosa
19’ Range near the Four Corners...E. leechi
20 Pronotum evenly tuberculate, range in Oregon...E. spoliata
20’ Pronotum punctate, range widespread...21
21 Antennas robust, body generally more robust...E. hirsuta
21’ Antennas thin, body generally more slender...E. pilosa
22 Size small or sometimes medium, covered in long setae, restricted to coastal and sometimes inland California, and the Baja peninsula, or rarely in the direction of and in Reno, or the Sonoran Desert...23
22’ Size small or large, usually glabrous, if with conspicuous setae then not found in coastal California, nor in the Baja California Peninsula, or the Sonoran Desert, and if found near Reno, Nevada, then third antennomere not shortened...28
23 Males with dentate profemora and elytra caudate, Sonoran Desert...E. tribulus
23’ Males nor females ever caudate or attenuate, coastal California and the Baja California Peninsula...24
24 Third antennomere shortened, body smaller and more slender, pill shaped, coastal California and towards and into Reno, Nevada...E. littoralis
24’ Third antennomere not shorted, body larger, California...25
25 Body larger, pronotum with constriction at base, if missing constriction then setae more dense...26
25’ Body smaller, pronotum lacking constriction at base, setae less dense...27
26 Setae orange, California and northern Baja California Peninsula...E. osculans
26’ Setae black or grey, California and northern Baja California Peninsula...E. ursus
27 Setae black, California and northern Baja California Peninsula...E. nigropilosa
27’ Setae yellow, Baja California Peninsula...E. subdeplanata
28 Elytra caudate at least in males and strongly muricate, near Tamaulipas if not caudate, size usually large...29
28’ Elytra caudate or not, but if caudate and muricately punctured then elytra only slightly muricate, elytra can be strongly muricate if not caudate and not near Tamaulipas, size large or small...31
29 Only males caudate with profemora dentate, Tamaulipas...E. fiski
29’ Both males and females caudate with mutic profemora, Four Corners and Sierra Nevada region...30
30 Elytra usually glabrous, rarely with setae, Four Corners...E. caudifera
30’ Elytra always with long setae, Sierra Nevada region...E. longipilosa
31 Elytral sculpture very rough, elytra always attenuate but never caudate, pronotum wide, restricted to California, or slightly into Nevada and Oregon...32
31’ Elytral sculpture variable but if rough then elytra never attenuate, widespread...33
32 Luster shiny and elytral apex acutely attenuate...E. marginata
32’ Luster dull and elytral apex blunt yet still attenuate...E. scabricula (E. acutangula)
33 Body oval shaped, coated in minute setae, coastal Texas and Louisiana...E. veterator
33’ Body shape variable, if small and shaped slightly oval then not found in coastal Texas or Louisiana...34
34 Body small and fusiform...35
34’ Body small or large, shape variable...37
35 Body nearly oval, clothed with minute setae, giving body a grey appearance, Great Plains of northern Texas to Canada...E. opaca
35’ Elytra highly punctured and glabrous...36
36 Body more fusiform, central and southern Great Plains...E. fusiformis
36’ Body less fusiform, the Sierra Nevadas to the Rocky Mountains, and the Arizona Sky Islands to British Colombia, northern Great Plains...E. extricata (in part)
37 Size medium to large, elytra usually inflated, wide, and large or sometimes flattened, especially in E. striolata, punctures either large, or appearing absent, although if elytra are not inflated, and attenuate, then punctures may be numerous and conspicuous, never sulcate...38
37’ Size variable but abdomen rarely inflated, if so, then punctures are small but conspicuous, sulcate or not...41
38 Elytral striae composed of large conspicuous punctures...E. goryi
38’ Elytral striae without large punctures...39
39 Elytra usually flattened, always attenuate, and heavily punctate, luster shiny, south and central Texas...E. striolata
39’ Elytra sometimes flattened, inconspicuous punctures present, luster usually dull, Arizona, New Mexico, and Sonora...40
40 Pronotum more or less parallel sided, anterolateral angles almost always projected outwards...E. subnitens
40’ Pronotum evenly arcuate, anterolateral angles only rarely projected outwards...E. madrensis
41 Size large sometimes medium or small in rare occasions, but almost always with legs long, sometimes caudate...42
41’ Size usually small, sometimes medium, if so then legs almost always short, never caudate...71
42 Body elongate, sometimes robust, pronotum not all that distinct from elytra, profemora never dentate and never with caudate elytra, punctures simple or muricate/scabrous, never sulcate...43
42’ Body fairly variable, sometimes elongate, often robust, pronotum usually quite distinct from elytra, males almost always with dentate profemora, elytra sometimes caudate, sulcate or not...48
43 Elytral punctures simple, anterolateral angles never very projected, body rarely flattened, but if so, then usually near the Sky Islands of southeast Arizona…45
43’ Elytral punctures not simple, anterolateral angles of pronotum projected, or body somewhat flattened and small, never in the Sky Islands…44
44 Anterolateral angles strongly projected, elytral punctures with tiny inconspicuous setae arising from each one, size usually not small...E. inornata
44’ Anterolateral angles not projected or only slightly projected, elytral punctures glabrous, size smaller, sometimes quite small…E. nigrina (continuation)
45 Elytra with red line running down the length of the elytra, this line never diffuses into black...E. ornatipennis
45’ Elytra entirely black, or if a red line is present along the elytra, it diffuses into black...46
46 Profemora strongly sinuate, pronotum widest slightly anterior of middle...E. hepburni
46’ Profemora simple, pronotum widest at middle...47
47 Prosternum horizontal, not projecting downwards, restricted to California...E. gigantea
47’ Prosternum projecting downwards, widespread but not found in California...E. longicollis
48 Elytra never completely smooth (muricate, irregularly punctured, sulcate even if sulci not deep), pronotum sometimes concave, body large, robust, and elytra with carina, if carina absent and body not very robust, then anterolateral angles of the pronotum rounded off, and the pronotum widest anterior of middle...49
48’ Elytra variable, often smooth, pronotum never concave, body variable, and elytra lacking carina, if elytra sulcate, or irregularly punctured, then pronotum widest at middle or with acute anterolateral angles...54
49 Pronotum concave...E. suturalis
49’ Pronotum convex...50
50 Elytra with carina...E. acuta
50’ Elytra without carina...51 (E. obscura)
51 Elytra sulcate...52
51’ Elytra not sulcate...53
52 Elytra deeply sulcate, west of the Great Plains...E. obscura sulcipennis
52’ Elytra slightly sulcate, Great Plains...E. obscura obscura
53 Elytra with simple punctures, western Texas...E. obscura glabrisulca
53’ Elytra with muricate punctures, Four Corners...E. obscura dispersa
54 Elytra with large glabrous costae, intervals minutely hirsute, often coated with white debris, males are caudate, females are sometimes slightly caudate, legs long...E. mirabilis
54’ Elytra variable but without costae, caudate or not...55
55 Pronotum very wide, humeral angles of elytra obsolete, never attenuate...E. grandicollis
55 Pronotum variable, if wide, then elytral apex attenuate at least, humeral angles of elytra not obsolete...56
56 Restricted to California and the Baja peninsula, never having deep sulci...57
56’ Widespread not found in California or the northern Baja peninsula, if found in California then elytra sulcate...63
57 Pronotum two times wider than the head...E. acuticauda
57’ Pronotum less then two times wider than the head...58
58 Pronotum more or less parallel sided, Mohave Desert...59
58’ Pronotum not parallel sided, or if so then elytral apex with groove in between both elytra, coastal and inland California…60
59 Tibia strongly curved, profemoral spines blunt, never caudate...E. subcylindrica
59’ Tibia not strongly curved, profemoral spines acute, males caudate...E. mexicana
60 Elytral punctures minute, pronotum nearly parallel sided, although sometimes slightly arcuate, elytral apex with groove in between both elytra…E. discincta
60’ Elytral punctures not minute, or if so then pronotum wide…61
61 Pronotum larger, elytral striae less prominent…E. dentipes
61’ Pronotum smaller, elytral striae more prominent…62
62 Pronotum widest anterior of middle, luster more shiny, elytra with simple punctures, glabrous, striae very clear…E. gracilis distans
62’ Pronotum widest at middle, luster more dull, elytra with muricate punctures and conspicuous setae, striae not clearly defined…E. adumbrata
63 Elytra strongly sulcate, at least on elytral apex…64
63’ Elytra not strongly sulcate…65
64 Pronotum widest anterior to middle…E. hispilabris
64’ Pronotum widest at middle…E. composita
65 Body flattened, elytra and pronotum not too distinctly separated, or if so then elytra remain wide up until their humeral angles…E. knullorum
65’ Body usually not flat, elytra and pronotum clearly separate, if elytra remain wide up until their humeral angles, then elytra inflated…66
66 Elytra with muricate punctures…67
66’ Elytra with simple punctures…68
67 Punctures of elytra arranged in rows and fairly muricate, elytral apex always caudate, even if short, El Paso region…E. tenuipes
67’ Punctures of elytra irregular and strongly muricate, elytral apex only sometimes attenuate, generally around the Four Corners and western Texas…E. sponsa
68 Hind angles of pronotum appearing rounded, size large, elytra often inflated and strongly convex, or fairly parallel sided…69 (E. spinipes)
68’ Hind angles of pronotum not rounded or only slightly rounded, size medium to large, elytra never inflated, but often parallel sided…70
69 Elytra more or less parallel sided, west of the Pecos River…E. spinipes macrura
69’ Elytra ventricose, east of the Pecos River…E. spinipes ventricosa
70 Anterolateral angles of pronotum always facing straight forward, never projecting outwards, male metatibia sinuate, males caudate, females strongly attenuate, strial punctures inconspicuous…E. eschscholtzii eschscholtzii
70’ Anterolateral angles of pronotum always projecting outwards at least a little, metatibia not abnormally sinuate, elytral apex only slightly attenuate, striae composed of rows of conspicuous punctures…E. gracilis gracilis
71 Elytra with conspicuous setae…72
71’ Elytra glabrous, or only with short inconspicuous setae…76
72 Size less than 12mm, elytra shiny with complex sculpturing, and covered in golden hairs, areas with sandy soils generally around the Four Corners…E. barbata
72’ Size usually small but rarely less than 12mm, elytra usually dull, sometimes shiny, never with golden hairs, usually in deserts above the Sonoran Desert…73
73 Size larger, body more robust, northern Arizona and southern Utah…E. halli
73’ Size smaller, body more slender, generally around the Great Basin and the Great Sand Dunes of Colorado…74
74 Distributed only in the Great Sand Dunes National Park…E. hirtipennis
74’ Distributed generally around the Great Basin…75
75 Setae black, generally around the Great Basin…E. letcheri
75’ Setae brownish, in and around Utah…E. aspera
76 Elytra flat and widened, about the same width as pronotum, sides sometimes slightly rounded or with carina…77
76’ Sides of elytra rounded evenly, generally elongate or circular…81
77 Body covered with minute setae, usually appearing grey in color…E. tricostata
77’ Body glabrous…78
78 Elytral sculpturing rough, striae vague to absent, luster generally dull…E. neomexicana
78’ Elytra with clear striae, luster shiny…79
79 Elytra with deeply impressed striae…E. pedinoides
79’ Elytra with slightly impressed striae…80 (E. wenzeli)
80 Punctures of elytra fine but easily noticeable…E. wenzeli speculicollis
80’ Punctures of elytra extremely fine and minute…E. wenzeli wenzeli
81 Both elytra with at least three large smooth costae, legs often dark red, southern Utah…E. parowana
81’ Both elytra without at least three large costae…82
82 Size small, elytral luster generally shiny, elytra only with conspicuous irregular punctures, never with tubercules…E. extricata (continuation)
82’ Size small to medium, luster variable although generally dull if elytra with irregular punctures, said irregular punctures also smaller, elytra with punctures in rows or irregular, or with tubercules, papillae, or rugae…83
83 Elytra generally inflated, if not, then elytra more or less parallel sided, usually tuberculate, larger protibial spur extending almost to third tarsomere, Pacific Northwest…E. humeralis
83’ Elytra inflated or not, but if with tubercules then elytra not inflated and not parallel sided, if without tubercules then not found in the Pacific Northwest, or if in the Pacific Northwest then pronotum not clearly widest in front of middle…84
84 Elytra with papillae, pronotum wide, California…E. papillosa
84’ Elytra without papillae…85
85 Elytra with coarse transverse tuberculate rugae, California…E. corvina
85’ Elytra without coarse transverse rugae, tuberculate or not…86
86 Elytra with large tubercules…87
86’ Elytra without large tubercules…88
87 Pronotum more or less arcuate and wider than long…E. granulata
87’ Pronotum more or less parallel sided and longer than wide…E. subtuberculata
88 Size small, pronotum evenly arcuate, lateral edges angular instead of rounded, punctures minute…E. arcuata
88’ Size variable, pronotum variable, but if arcuate, then lateral edges rounded…89
89 Luster shiny, elytral punctures large and in rows, outer protibial spur clearly larger than inner protibial spur…E. debilis
89’ Luster variable but usually not too shiny, punctures variable but rarely large, if protibial spurs disproportionate in size, then elytra with small punctures or tubercules…90
90 Longer protibial spur extending to almost to the third tarsomere…91 (E. rileyi)
90’ Longer protibial spur extending only to apex of the first tarsomere…92
91 Elytra shiny with prominent striae, Four Corners…E. rileyi reducta
91’ Elytra dull without very prominent striae, widespread…E. rileyi rileyi
92 “…longer protibial spur evenly tapering to a point from base to apex”…E. carbonaria (see Thomas 2012 for subspecies key)
92’ “…longer protibial spur parallel sided in basal half then tapering to a point at apex”…93
93 Elytral punctures irregular, San Francisco region…E. quadricollis
93’ Elytral punctures organized in rows, southeast Arizona…94 (E. anthracina)
94 Size larger, elytral punctures less fine, widespread…E. anthracina anthracina
94’ Size smaller, elytral punctures more fine, Chiricahua Mountains…E. anthracina lustrans

Another quick update, this version should hopefully last for more than a week! One last species had been forgotten since the beginning, initially I forgot E. wynnei, then I added it in V1.1, then I forgot E. barbata, then I added it in V2.1, then I realized that I actually accidentally removed E. corvina in V2.0, so it was readded in V2.4, and finally, today I realized that I had forgotten E. spiculifera, so now in V2.5 it is finally being added, and I did double check that every species was included, which they are. I also improved the Metablapylis section. More info in my profile: https://www.inaturalist.org/people/6449260

1 Mesofemora and metafemora dentate or subdentate...2
1’ Mesofemora and metafemora never dentate...4
2 Elytral punctures strongly muricate...E. moesta
2’ Elytral punctures simple or slightly muricate...3
3 Pronotum widest anterior of middle, femoral spines large...E. armata
3’ Pronotum widest at middle, femoral spines small to medium sized...E. femorata
4 Body small, pronotum generally cordate and constricted at base, elytra apex not attenuate or caudate, roughly sculptured, never sulcate, sometimes with short setae, usually distributed across beaches, forests, and mountains, rarely in arid regions...subgenus Blapylis
4’ Body small or large, pronotum usually not cordate although often slightly constricted at base, elytral apex attenuate, caudate or neither, roughly sculptured or not, sulcate or not, with setae or not, widespread across all environments...5
5 Legs long with unproportionately small body, robust or not, body often flattened if not robust, never sulcate, if legs not abnormally long, then body elongate and flattened...6
5’ Legs long or short but with body fairly proportionate, only rarely flattened, sulcate or not, if legs fairly long, then not with conspicuous setae, or a small, elongate, and flattened body...22
6 Body generally slender and flattened, pronotal and elytral sculpturing simple (except in E. nigrina), never with conspicuous setae...7
6’ Body, generally robust, never flattened, pronotal and elytral sculpturing complex, usually with conspicuous setae...18
7 Elytral sculpturing muricate or scabrous, southern New Mexico to Canada, Sierra Nevada Mountains to Rocky Mountains...E. nigrina (in part)
7’ Elytral sculpturing simple, always below the northernmost edge of Colorado’s border...8
8 Range only in Inyo White Mountains...9
8’ Range widespread...10
9 Profemora with blunt tooth, anterolateral angles of pronotum blunt but projected, legs shorter...E. aalbui
9’ Profemora only sinuate, anterolateral angles of pronotum slightly projected, legs longer...E. microps
10 Range near Big Bend National Park and the Guadalupe Mountains...11
10’ Range in the Southwest United States excluding Texas and the Guadalupe Mountains...13
11 Range in the Guadalupe Mountains...E. guadalupensis
11’ Range near Big Bend National Park...12
12 Mentum with finger-like process, pronotum lacking projected anterolateral angles, widest at middle, near Rio Grande river...E. labialis
12’ Mentum without finger-like process, pronotum with slightly projected anterolateral angles, Big Bend National Park...E. easterlai
13 Range in the Mohave Desert of California, pronotum usually evenly arcuate, strial punctures larger than those of intervals...E. californica
13’ Range in Arizona, Utah, and the Mohave Desert, pronotum rarely evenly arcuate, strial punctures variable, but if in the Mohave Desert then those of striae and intervals small and subequal in size...14
14 Range in the Sonoran Desert or the most western portion of the Arizona-Utah border...15
14’ Range in the Sky Islands or the Colorado Plateau...16
15 Anterolateral angles strongly projected, caves by the most western point of the Arizona-Utah border…E. wynnei
15’ Anterolateral angles not strongly projected, the Sonoran and southern Mohave Deserts…E. delicata (E. nevadensis)
16 Body elongate, northern Arizona and southern Utah...17
16’ Body not elongate, Sky Islands in southeast Arizona...E. dissimilis
17 Strial punctures larger than punctures of intervals, anterolateral edge of pronotum truncate, restricted to the Grand Canyon...E. leptoscelis
17’ Strial punctures subequal to punctures of intervals, anterolateral edge of pronotum not truncate, or only slightly truncate, northern Arizona and southern Utah...E. wheeleri
18 Large tubercles present on Elytra...19
18’ Elytra without large tubercules...20
19 Range in Sierra Nevada region...E. granosa
19’ Range near the Four Corners...E. leechi
20 Pronotum evenly tuberculate, range in Oregon...E. spoliata
20’ Pronotum punctate, range widespread...21
21 Antennas robust, body generally more robust...E. hirsuta
21’ Antennas thin, body generally more slender...E. pilosa
22 Size small or sometimes medium, covered in long setae, restricted to coastal and sometimes inland California, and the Baja peninsula, or rarely in the direction of and in Reno, or the Sonoran Desert...23
22’ Size small or large, usually glabrous, if with conspicuous setae then not found in coastal California, nor in the Baja California Peninsula, or the Sonoran Desert, and if found near Reno, Nevada, then third antennomere not shortened...28
23 Males with dentate profemora and elytra caudate, Sonoran Desert...E. tribulus
23’ Males nor females ever caudate or attenuate, coastal California and the Baja California Peninsula...24
24 Third antennomere shortened, body smaller and more slender, pill shaped, coastal California and towards and into Reno, Nevada...E. littoralis
24’ Third antennomere not shorted, body larger, California...25
25 Body larger, pronotum with constriction at base, if missing constriction then setae more dense...26
25’ Body smaller, pronotum lacking constriction at base, setae less dense...27
26 Setae orange, California and northern Baja California Peninsula...E. osculans
26’ Setae black or grey, California and northern Baja California Peninsula...E. ursus
27 Setae black, California and northern Baja California Peninsula...E. nigropilosa
27’ Setae yellow, Baja California Peninsula...E. subdeplanata
28 Elytra caudate at least in males and strongly muricate, near Tamaulipas if not caudate, size usually large...29
28’ Elytra caudate or not, but if caudate and muricately punctured then elytra only slightly muricate, elytra can be strongly muricate if not caudate and not near Tamaulipas, size large or small...31
29 Only males caudate with profemora dentate, Tamaulipas...E. fiski
29’ Both males and females caudate with mutic profemora, Four Corners and Sierra Nevada region...30
30 Elytra usually glabrous, rarely with setae, Four Corners...E. caudifera
30’ Elytra always with long setae, Sierra Nevada region...E. longipilosa
31 Elytral sculpture very rough, elytra always attenuate but never caudate, pronotum wide, restricted to California, or slightly into Nevada and Oregon...32
31’ Elytral sculpture variable but if rough then elytra never attenuate, widespread...33
32 Luster shiny and elytral apex acutely attenuate, Pacific coast...E. marginata
32’ Luster dull and elytral apex blunt yet still attenuate, Sierra Nevada Mountains...E. scabricula (E. acutangula)
33 Body oval shaped, coated in minute setae, coastal Texas and Louisiana...E. veterator
33’ Body shape variable, if small and shaped slightly oval then not found in coastal Texas or Louisiana...34
34 Body small and fusiform...35
34’ Body small or large, shape variable...37
35 Body nearly oval, clothed with minute setae, giving body a grey appearance, Great Plains of northern Texas to Canada...E. opaca
35’ Elytra highly punctured and glabrous...36
36 Body more fusiform, central and southern Great Plains...E. fusiformis
36’ Body less fusiform, the Sierra Nevadas to the Rocky Mountains, and the Arizona Sky Islands to British Colombia, northern Great Plains...E. extricata (in part)
37 Size medium to large, elytra usually inflated, wide, and large or sometimes flattened, especially in E. striolata, punctures either large, or appearing absent, although if elytra are not inflated, and attenuate, then punctures may be numerous and conspicuous, never sulcate...38
37’ Size variable but abdomen rarely inflated, if so, then punctures are small but conspicuous, sulcate or not...42
38 Elytral striae composed of large conspicuous punctures...E. goryi
38’ Elytral striae without large punctures...39
39 Elytra usually flattened, always attenuate, and heavily punctate, luster shiny, south and central Texas...E. striolata
39’ Elytra sometimes flattened, inconspicuous punctures present, although sometimes numerous and fairly noticeable, luster usually dull, Arizona, New Mexico, and Texas...40
40 Pronotum evenly arcuate and with anterolateral angles never projecting outwards, body grayish in color, covered in small punctures, Texas…E. spiculifera
40’ Pronotum parallel sided or evenly arcuate, anterolateral angles projecting outwards or not, color black, punctures inconspicuous, Arizona and New Mexico…41
41 Pronotum more or less parallel sided, anterolateral angles almost always projected outwards...E. subnitens
41’ Pronotum evenly arcuate, anterolateral angles only rarely projected outwards...E. madrensis
42 Size large sometimes medium or small in rare occasions, but almost always with legs long, sometimes caudate...43
42’ Size usually small, sometimes medium, if so then legs almost always short, never caudate...72
43 Body elongate, sometimes robust, pronotum not all that distinct from elytra, profemora never dentate and never with caudate elytra, punctures simple or muricate/scabrous, never sulcate...44
43’ Body fairly variable, sometimes elongate, often robust, pronotum usually quite distinct from elytra, males almost always with dentate profemora, elytra sometimes caudate, sulcate or not...49
44 Elytral punctures simple, anterolateral angles never very projected, body rarely flattened, but if so, then usually near the Sky Islands of southeast Arizona…46
44’ Elytral punctures not simple, anterolateral angles of pronotum projected, or body somewhat flattened and small, never in the Sky Islands…45
45 Anterolateral angles strongly projected, elytral punctures with tiny inconspicuous setae arising from each one, size usually not small...E. inornata
45’ Anterolateral angles not projected or only slightly projected, elytral punctures glabrous, size smaller, sometimes quite small…E. nigrina (continuation)
46 Elytra with red line running down the length of the elytra, this line never diffuses into black...E. ornatipennis
46’ Elytra entirely black, or if a red line is present along the elytra, it diffuses into black...47
47 Profemora strongly sinuate, pronotum widest slightly anterior of middle...E. hepburni
47’ Profemora simple, pronotum widest at middle...48
48 Prosternum horizontal, not projecting downwards, restricted to California...E. gigantea
48’ Prosternum projecting downwards, widespread but not found in California...E. longicollis
49 Elytra never completely smooth (muricate, irregularly punctured, sulcate even if sulci not deep), pronotum sometimes concave, body large, robust, and elytra with carina, if carina absent and body not very robust, then anterolateral angles of the pronotum rounded off, and the pronotum widest anterior of middle...50
49’ Elytra variable, often smooth, pronotum never concave, body variable, and elytra lacking carina, if elytra sulcate, or irregularly punctured, then pronotum widest at middle or with acute anterolateral angles...55
50 Pronotum concave...E. suturalis
50’ Pronotum convex...51
51 Elytra with carina...E. acuta
51’ Elytra without carina...52 (E. obscura)
52 Elytra sulcate...53
52’ Elytra not sulcate...54
53 Elytra deeply sulcate, west of the Great Plains...E. obscura sulcipennis
53’ Elytra slightly sulcate, Great Plains...E. obscura obscura
54 Elytra with simple punctures, western Texas...E. obscura glabrisulca
54’ Elytra with muricate punctures, Four Corners...E. obscura dispersa
55 Elytra with large glabrous costae, intervals minutely hirsute, often coated with white debris, males are caudate, females are sometimes slightly caudate, legs long...E. mirabilis
55’ Elytra variable but without costae, caudate or not...56
56 Pronotum very wide, humeral angles of elytra obsolete, never attenuate...E. grandicollis
56’ Pronotum variable, if wide, then elytral apex attenuate at least, humeral angles of elytra not obsolete...57
57 Restricted to California and the Baja peninsula, never having deep sulci...58
57’ Widespread not found in California or the northern Baja peninsula, if found in California then elytra sulcate...64
58 Pronotum two times wider than the head...E. acuticauda
58’ Pronotum less then two times wider than the head...59
59 Pronotum more or less parallel sided, Mohave Desert...60
59’ Pronotum not parallel sided, or if so then elytral apex with groove in between both elytra, coastal and inland California…61
60 Tibia strongly curved, profemoral spines blunt, never caudate...E. subcylindrica
60’ Tibia not strongly curved, profemoral spines acute, males caudate...E. mexicana
61 Elytral punctures minute, pronotum nearly parallel sided, although sometimes slightly arcuate, elytral apex with groove in between both elytra…E. discincta
61’ Elytral punctures not minute, or if so then pronotum wide…62
62 Pronotum larger, elytral striae less prominent…E. dentipes
62’ Pronotum smaller, elytral striae more prominent…63
63 Pronotum widest anterior of middle, luster more shiny, elytra with simple punctures, glabrous, striae very clear…E. gracilis distans
63’ Pronotum widest at middle, luster more dull, elytra with muricate punctures and conspicuous setae, striae not clearly defined…E. adumbrata
64 Elytra strongly sulcate, at least on elytral apex…65
64’ Elytra not strongly sulcate…66
65 Pronotum widest anterior to middle…E. hispilabris
65’ Pronotum widest at middle…E. composita
66 Body flattened, elytra and pronotum not too distinctly separated, or if so then elytra remain wide up until their humeral angles…E. knullorum
66’ Body usually not flat, elytra and pronotum clearly separate, if elytra remain wide up until their humeral angles, then elytra inflated…67
67 Elytra with muricate punctures…68
67’ Elytra with simple punctures…69
68 Punctures of elytra arranged in rows and fairly muricate, elytral apex always caudate, even if short, El Paso region…E. tenuipes
68’ Punctures of elytra irregular and strongly muricate, elytral apex only sometimes attenuate, generally around the Four Corners and western Texas…E. sponsa
69 Hind angles of pronotum appearing rounded, size large, elytra often inflated and strongly convex, or fairly parallel sided…70 (E. spinipes)
69’ Hind angles of pronotum not rounded or only slightly rounded, size medium to large, elytra never inflated, but often parallel sided…71
70 Elytra more or less parallel sided, west of the Pecos River…E. spinipes macrura
70’ Elytra ventricose, east of the Pecos River…E. spinipes ventricosa
71 Anterolateral angles of pronotum always facing straight forward, never projecting outwards, male metatibia sinuate, males caudate, females strongly attenuate, strial punctures inconspicuous…E. eschscholtzii eschscholtzii
71’ Anterolateral angles of pronotum always projecting outwards at least a little, metatibia not abnormally sinuate, elytral apex only slightly attenuate, striae composed of rows of conspicuous punctures…E. gracilis gracilis
72 Elytra with conspicuous setae…73
72’ Elytra glabrous, or only with short inconspicuous setae…77
73 Size less than 12mm, elytra shiny with complex sculpturing, and covered in golden hairs, areas with sandy soils generally around the Four Corners…E. barbata
73’ Size usually small but rarely less than 12mm, elytra usually dull, sometimes shiny, never with golden hairs, usually in deserts above the Sonoran Desert…74
74 Size larger, body more robust, northern Arizona and southern Utah…E. halli
74’ Size smaller, body more slender, generally around the Great Basin and the Great Sand Dunes of Colorado…75
75 Distributed only in the Great Sand Dunes National Park…E. hirtipennis
75’ Distributed generally around the Great Basin…76
76 Setae black, generally around the Great Basin…E. letcheri
76’ Setae brownish, in and around Utah…E. aspera
77 Elytra flat and widened, about the same width as pronotum, sides sometimes slightly rounded or with carina…78
77’ Sides of elytra rounded evenly, generally elongate or circular…82
78 Body covered with minute setae, usually appearing grey in color…E. tricostata
78’ Body glabrous…79
79 Elytral sculpturing rough, striae vague to absent, luster generally dull…E. neomexicana
79’ Elytra with clear striae, luster shiny…80
80 Elytra with deeply impressed striae…E. pedinoides
80’ Elytra with slightly impressed striae…80 (E. wenzeli)
81 Punctures of elytra fine but easily noticeable…E. wenzeli speculicollis
81’ Punctures of elytra extremely fine and minute…E. wenzeli wenzeli
82 Both elytra with at least three large smooth costae, legs often dark red, southern Utah…E. parowana
82’ Both elytra without at least three large costae…83
83 Size small, elytral luster generally shiny, elytra only with conspicuous irregular punctures, never with tubercules…E. extricata (continuation)
83’ Size small to medium, luster variable although generally dull if elytra with irregular punctures, said irregular punctures also smaller, elytra with punctures in rows or irregular, or with tubercules, papillae, or rugae…84
84 Elytra generally inflated, if not, then elytra more or less parallel sided, usually tuberculate, larger protibial spur extending almost to third tarsomere, Pacific Northwest…E. humeralis
84’ Elytra inflated or not, but if with tubercules then elytra not inflated and not parallel sided, if without tubercules then not found in the Pacific Northwest, or if in the Pacific Northwest then pronotum not clearly widest in front of middle…85
85 Elytra with papillae, pronotum wide, California…E. papillosa
85’ Elytra without papillae…86
86 Elytra with coarse transverse tuberculate rugae, California…E. corvina
86’ Elytra without coarse transverse rugae, tuberculate or not…87
87 Elytra with large tubercules…88
87’ Elytra without large tubercules…89
88 Pronotum more or less arcuate and wider than long…E. granulata
88’ Pronotum more or less parallel sided and longer than wide…E. subtuberculata
89 Size small, pronotum evenly arcuate, lateral edges angular instead of rounded, punctures minute…E. arcuata
89’ Size variable, pronotum variable, but if arcuate, then lateral edges rounded…90
90 Luster shiny, elytral punctures large and in rows, outer protibial spur clearly larger than inner protibial spur…E. debilis
90’ Luster variable but usually not too shiny, punctures variable but rarely large, if protibial spurs disproportionate in size, then elytra with small punctures or tubercules…91
91 Longer protibial spur extending to almost to the third tarsomere…92 (E. rileyi)
91’ Longer protibial spur extending only to apex of the first tarsomere…93
92 Elytra shiny with prominent striae, Four Corners…E. rileyi reducta
92’ Elytra dull without very prominent striae, widespread…E. rileyi rileyi
93 “…longer protibial spur evenly tapering to a point from base to apex”…E. carbonaria (see Thomas 2012 for subspecies key)
93’ “…longer protibial spur parallel sided in basal half then tapering to a point at apex”…94
94 Elytral punctures irregular, San Francisco region…E. quadricollis
94’ Elytral punctures organized in rows, southeast Arizona…95 (E. anthracina)
95 Size larger, elytral punctures less fine, widespread…E. anthracina anthracina
95’ Size smaller, elytral punctures more fine, Chiricahua Mountains…E. anthracina lustrans

Once again another minor update, although one that should greatly aid one in certain identifications. The two statements of 42 finally have a clear definition, and five species in the nominate subgenus, including E. spinipes, have had their statements reworked. More info in my profile: https://www.inaturalist.org/people/6449260

1 Mesofemora and metafemora dentate or subdentate...2
1’ Mesofemora and metafemora never dentate...4
2 Elytral punctures strongly muricate...E. moesta
2’ Elytral punctures simple or slightly muricate...3
3 Pronotum widest anterior of middle, femoral spines large...E. armata
3’ Pronotum widest at middle, femoral spines small to medium sized...E. femorata
4 Body small, pronotum generally cordate and constricted at base, elytra apex not attenuate or caudate, roughly sculptured, never sulcate, sometimes with short setae, usually distributed across beaches, forests, and mountains, rarely in arid regions...subgenus Blapylis
4’ Body small or large, pronotum usually not cordate although often slightly constricted at base, elytral apex attenuate, caudate or neither, roughly sculptured or not, sulcate or not, with setae or not, widespread across all environments...5
5 Legs long with unproportionately small body, robust or not, body often flattened if not robust, never sulcate, if legs not abnormally long, then body elongate and flattened...6
5’ Legs long or short but with body fairly proportionate, only rarely flattened, sulcate or not, if legs fairly long, then not with conspicuous setae, or a small, elongate, and flattened body...22
6 Body generally slender and flattened, pronotal and elytral sculpturing simple (except in E. nigrina), never with conspicuous setae...7
6’ Body, generally robust, never flattened, pronotal and elytral sculpturing complex, usually with conspicuous setae...18
7 Elytral sculpturing muricate or scabrous, southern New Mexico to Canada, Sierra Nevada Mountains to Rocky Mountains...E. nigrina (in part)
7’ Elytral sculpturing simple, always below the northernmost edge of Colorado’s border...8
8 Range only in Inyo White Mountains...9
8’ Range widespread...10
9 Profemora with blunt tooth, anterolateral angles of pronotum blunt but projected, legs shorter...E. aalbui
9’ Profemora only sinuate, anterolateral angles of pronotum slightly projected, legs longer...E. microps
10 Range near Big Bend National Park and the Guadalupe Mountains...11
10’ Range in the Southwest United States excluding Texas and the Guadalupe Mountains...13
11 Range in the Guadalupe Mountains...E. guadalupensis
11’ Range near Big Bend National Park...12
12 Mentum with finger-like process, pronotum lacking projected anterolateral angles, widest at middle, near Rio Grande river...E. labialis
12’ Mentum without finger-like process, pronotum with slightly projected anterolateral angles, Big Bend National Park...E. easterlai
13 Range in the Mohave Desert of California, pronotum usually evenly arcuate, strial punctures larger than those of intervals...E. californica
13’ Range in Arizona, Utah, and the Mohave Desert, pronotum rarely evenly arcuate, strial punctures variable, but if in the Mohave Desert then those of striae and intervals small and subequal in size...14
14 Range in the Sonoran Desert or the most western portion of the Arizona-Utah border...15
14’ Range in the Sky Islands or the Colorado Plateau...16
15 Anterolateral angles strongly projected, caves by the most western point of the Arizona-Utah border…E. wynnei
15’ Anterolateral angles not strongly projected, the Sonoran and southern Mohave Deserts…E. delicata (E. nevadensis)
16 Body elongate, northern Arizona and southern Utah...17
16’ Body not elongate, Sky Islands in southeast Arizona...E. dissimilis
17 Strial punctures larger than punctures of intervals, anterolateral edge of pronotum truncate, restricted to the Grand Canyon...E. leptoscelis
17’ Strial punctures subequal to punctures of intervals, anterolateral edge of pronotum not truncate, or only slightly truncate, northern Arizona and southern Utah...E. wheeleri
18 Large tubercles present on Elytra...19
18’ Elytra without large tubercules...20
19 Range in Sierra Nevada region...E. granosa
19’ Range near the Four Corners...E. leechi
20 Pronotum evenly tuberculate, range in Oregon...E. spoliata
20’ Pronotum punctate, range widespread...21
21 Antennas robust, body generally more robust...E. hirsuta
21’ Antennas thin, body generally more slender...E. pilosa
22 Size small or sometimes medium, covered in long setae, restricted to coastal and sometimes inland California, and the Baja peninsula, or rarely in the direction of and in Reno, or the Sonoran Desert...23
22’ Size small or large, usually glabrous, if with conspicuous setae then not found in coastal California, nor in the Baja California Peninsula, or the Sonoran Desert, and if found near Reno, Nevada, then third antennomere not shortened...28
23 Males with dentate profemora and elytra caudate, Sonoran Desert...E. tribulus
23’ Males nor females ever caudate or attenuate, coastal California and the Baja California Peninsula...24
24 Third antennomere shortened, body smaller and more slender, pill shaped, coastal California and towards and into Reno, Nevada...E. littoralis
24’ Third antennomere not shorted, body larger, California...25
25 Body larger, pronotum with constriction at base, if missing constriction then setae more dense...26
25’ Body smaller, pronotum lacking constriction at base, setae less dense...27
26 Setae orange, California and northern Baja California Peninsula...E. osculans
26’ Setae black or grey, California and northern Baja California Peninsula...E. ursus
27 Setae black, California and northern Baja California Peninsula...E. nigropilosa
27’ Setae yellow, Baja California Peninsula...E. subdeplanata
28 Elytra caudate at least in males and strongly muricate, near Tamaulipas if not caudate, size usually large...29
28’ Elytra caudate or not, but if caudate and muricately punctured then elytra only slightly muricate, elytra can be strongly muricate if not caudate and not near Tamaulipas, size large or small...31
29 Only males caudate with profemora dentate, Tamaulipas...E. fiski
29’ Both males and females caudate with mutic profemora, Four Corners and Sierra Nevada region...30
30 Elytra usually glabrous, rarely with setae, Four Corners...E. caudifera
30’ Elytra always with long setae, Sierra Nevada region...E. longipilosa
31 Elytral sculpture very rough, elytra always attenuate but never caudate, pronotum wide, restricted to California, or slightly into Nevada and Oregon...32
31’ Elytral sculpture variable but if rough then elytra never attenuate, widespread...33
32 Luster shiny and elytral apex acutely attenuate, Pacific coast...E. marginata
32’ Luster dull and elytral apex blunt yet still attenuate, Sierra Nevada Mountains...E. scabricula (E. acutangula)
33 Body oval shaped, coated in minute setae, coastal Texas and Louisiana...E. veterator
33’ Body shape variable, if small and shaped slightly oval then not found in coastal Texas or Louisiana...34
34 Body small and fusiform...35
34’ Body small or large, shape variable...37
35 Body nearly oval, clothed with minute setae, giving body a grey appearance, Great Plains of northern Texas to Canada...E. opaca
35’ Elytra highly punctured and glabrous...36
36 Body more fusiform, central and southern Great Plains...E. fusiformis
36’ Body less fusiform, the Sierra Nevadas to the Rocky Mountains, and the Arizona Sky Islands to British Colombia, northern Great Plains...E. extricata (in part)
37 Size medium to large, elytra usually inflated, wide, and large or sometimes flattened, especially in E. striolata, punctures either large, or appearing absent, although if elytra are not inflated, and attenuate, then punctures may be numerous and conspicuous, never sulcate...38
37’ Size variable but abdomen rarely inflated, if so, then punctures are small but conspicuous, sulcate or not...42
38 Elytral striae composed of large conspicuous punctures...E. goryi
38’ Elytral striae without large punctures...39
39 Elytra usually flattened, always attenuate, and heavily punctate, luster shiny, south and central Texas...E. striolata
39’ Elytra sometimes flattened, inconspicuous punctures present, although sometimes numerous and fairly noticeable, luster usually dull, Arizona, New Mexico, and Texas...40
40 Pronotum evenly arcuate and with anterolateral angles never projecting outwards, body grayish in color, covered in small punctures, Texas…E. spiculifera
40’ Pronotum parallel sided or evenly arcuate, anterolateral angles projecting outwards or not, color black, punctures inconspicuous, Arizona and New Mexico…41
41 Pronotum more or less parallel sided, anterolateral angles almost always projected outwards...E. subnitens
41’ Pronotum evenly arcuate, anterolateral angles only rarely projected outwards...E. madrensis
42 Size almost always larger than 17mm, in rare cases reaching 14mm, but almost always with legs long, no matter the size, sometimes caudate...43
42’ Size almost always smaller than 17mm, if larger then legs almost always short, legs are often long if body in normal size range, never caudate...72
43 Body elongate, sometimes robust, pronotum not all that distinct from elytra, profemora never dentate and never with caudate elytra, punctures simple or muricate/scabrous, never sulcate...44
43’ Body fairly variable, sometimes elongate, often robust, pronotum usually quite distinct from elytra, males almost always with dentate profemora, elytra sometimes caudate, sulcate or not...49
44 Elytral punctures simple, anterolateral angles never very projected, body rarely flattened, but if so, then usually near the Sky Islands of southeast Arizona…46
44’ Elytral punctures not simple, anterolateral angles of pronotum projected, or body somewhat flattened and small, never in the Sky Islands…45
45 Anterolateral angles strongly projected, elytral punctures with tiny inconspicuous setae arising from each one, size usually not small...E. inornata
45’ Anterolateral angles not projected or only slightly projected, elytral punctures glabrous, size smaller, sometimes quite small…E. nigrina (continuation)
46 Elytra with red line running down the length of the elytra, this line never diffuses into black...E. ornatipennis
46’ Elytra entirely black, or if a red line is present along the elytra, it diffuses into black...47
47 Profemora strongly sinuate, pronotum widest slightly anterior of middle...E. hepburni
47’ Profemora simple, pronotum widest at middle...48
48 Prosternum horizontal, not projecting downwards, restricted to California...E. gigantea
48’ Prosternum projecting downwards, widespread but not found in California...E. longicollis
49 Elytra with carina, if carina absent and the elytra either sulcate or with numerous irregular punctures, then anterolateral angles of the pronotum rounded off and the pronotum widest anterior of middle, pronotum concave or convex...50
49’ Elytra lacking carina, if elytra sulcate or with numerous irregular punctures, then anterolateral angles of the pronotum acute, or if angles not acute then pronotum widest at middle, pronotum convex...55
50 Pronotum concave...E. suturalis
50’ Pronotum convex...51
51 Elytra with carina...E. acuta
51’ Elytra without carina...52 (E. obscura)
52 Elytra sulcate...53
52’ Elytra not sulcate...54
53 Elytra deeply sulcate, west of the Great Plains...E. obscura sulcipennis
53’ Elytra slightly sulcate, Great Plains...E. obscura obscura
54 Elytra with simple punctures, western Texas...E. obscura glabrisulca
54’ Elytra with muricate punctures, Four Corners...E. obscura dispersa
55 Elytra with large glabrous costae, intervals minutely hirsute, often coated with white debris, males are caudate, females are sometimes slightly caudate, legs long...E. mirabilis
55’ Elytra variable but without costae, caudate or not...56
56 Pronotum usually wide, humeral angles of elytra obsolete, never attenuate...E. grandicollis
56’ Pronotum variable, if wide, then elytral apex attenuate at least, humeral angles of elytra not obsolete...57
57 Restricted to California and the Baja California peninsula, never having deep sulci, if not in California then tibia strongly curved and profemoral spine small and blunt and in Nevada or northwest Arizona...58
57’ Widespread not found in California or the northern Baja California peninsula, if found in California then elytra sulcate, never in Nevada or northwest Arizona unless elytra sulcate...64
58 Pronotum two times wider than the head...E. acuticauda
58’ Pronotum less then two times wider than the head...59
59 Pronotum more or less parallel sided, widest at middle, Mohave Desert, Nevada, Arizona...60
59’ Pronotum not parallel sided, or if so then elytral apex with groove in between both elytra, if in the Mohave Desert then pronotum widest anterior of middle…61
60 Tibia strongly curved, profemoral spines blunt, never caudate...E. subcylindrica
60’ Tibia not strongly curved, profemoral spines acute, males caudate...E. mexicana
61 Elytral punctures minute, pronotum nearly parallel sided, although sometimes slightly arcuate, elytral apex with groove in between both elytra…E. discincta
61’ Elytral punctures not minute, or if so then pronotum wide…62
62 Pronotum larger, elytral striae less prominent…E. dentipes
62’ Pronotum smaller, elytral striae more prominent…63
63 Pronotum widest anterior of middle, luster more shiny, elytra with simple punctures, glabrous, striae very clear, mainland southern California…E. gracilis distans
63’ Pronotum widest at middle, luster more dull, elytra with muricate punctures and conspicuous setae, striae not clearly defined, Channel Islands…E. adumbrata
64 Elytra strongly sulcate, at least on elytral apex…65
64’ Elytra not strongly sulcate…66
65 Pronotum widest anterior to middle, anterolateral angles of pronotum acute…E. hispilabris
65’ Pronotum widest at middle, anterolateral angles of pronotum rounded off…E. composita
66 Body flattened, elytra and pronotum not too distinctly separated, or if so then elytra remain wide up until their humeral angles…E. knullorum
66’ Body usually not flat, elytra and pronotum clearly separate, if elytra remain wide up until their humeral angles, then elytra inflated…67
67 Elytra strongly muricate, never caudate…E. sponsa
67’ Elytra with simple punctures or only slightly muricate, mainly at the elytral apex…68
68 Anterolateral angles of pronotum facing straight forward or only slightly projected outwards, males caudate and with the metatibia sinuate, southern Arizona…E. eschscholtzii eschscholtzii
68’ If in southern Arizona then anterolateral angles of pronotum projecting outwards, or hind angles of pronotum appearing quite rounded…69
69 Hind angles of pronotum appearing rounded, size large, elytra often inflated and strongly convex, or fairly parallel sided…70 (E. spinipes)
69’ Hind angles of pronotum not rounded or only slightly rounded, size medium to large, elytra never inflated, but often parallel sided…71
70 Elytra more or less parallel sided, west of the Pecos River…E. spinipes macrura
70’ Elytra ventricose, east of the Pecos River…E. spinipes ventricosa
71 Elytra caudate or strongly attenuate, El Paso region…E. tenuipes
71’ Elytra at most slightly attenuate…E. gracilis gracilis
72 Elytra with conspicuous setae…73
72’ Elytra glabrous, or only with short inconspicuous setae…77
73 Size less than 12mm, elytra shiny with complex sculpturing, and covered in golden hairs, areas with sandy soils generally around the Four Corners…E. barbata
73’ Size usually small but rarely less than 12mm, elytra usually dull, sometimes shiny, never with golden hairs, usually in deserts above the Sonoran Desert…74
74 Size larger, body more robust, northern Arizona and southern Utah…E. halli
74’ Size smaller, body more slender, generally around the Great Basin or the Great Sand Dunes of Colorado…75
75 Distributed only in the Great Sand Dunes National Park…E. hirtipennis
75’ Distributed generally around the Great Basin…76
76 Setae black, generally around the Great Basin…E. letcheri
76’ Setae brownish, in and around Utah…E. aspera
77 Elytra flat and widened, about the same width as pronotum, sides sometimes slightly rounded or with carina…78
77’ Sides of elytra rounded evenly, generally elongate or circular…82
78 Body covered with minute setae, usually appearing grey in color…E. tricostata
78’ Body glabrous…79
79 Elytral sculpturing rough, striae vague to absent, luster generally dull…E. neomexicana
79’ Elytra with clear striae, luster shiny…80
80 Elytra with deeply impressed striae…E. pedinoides
80’ Elytra with slightly impressed striae…80 (E. wenzeli)
81 Punctures of elytra fine but easily noticeable…E. wenzeli speculicollis
81’ Punctures of elytra extremely fine and minute…E. wenzeli wenzeli
82 Both elytra with at least three large smooth costae, legs often dark red, southern Utah…E. parowana
82’ Both elytra without at least three large costae…83
83 Size small, elytral luster generally shiny, elytra only with conspicuous irregular punctures, never with tubercules…E. extricata (continuation)
83’ Size small to medium, luster variable although generally dull if elytra with irregular punctures, said irregular punctures also smaller, elytra with punctures in rows or irregular, or with tubercules, papillae, or rugae…84
84 Elytra generally inflated, if not, then elytra more or less parallel sided, usually tuberculate, larger protibial spur extending almost to third tarsomere, Pacific Northwest…E. humeralis
84’ Elytra inflated or not, but if with tubercules then elytra not inflated and not parallel sided, if without tubercules then not found in the Pacific Northwest, or if in the Pacific Northwest then pronotum not clearly widest in front of middle…85
85 Elytra with papillae, pronotum wide, luster dull, California…E. papillosa
85’ Elytra without papillae, luster variable…86
86 Elytra with coarse transverse tuberculate rugae, luster shiny…E. corvina
86’ Elytra without coarse transverse rugae, tuberculate or not, luster variable…87
87 Elytra with large tubercules…88
87’ Elytra without large tubercules…89
88 Pronotum more or less arcuate and wider than long…E. granulata
88’ Pronotum more or less parallel sided and longer than wide…E. subtuberculata
89 Size small, pronotum evenly arcuate, lateral edges angular instead of rounded, punctures minute…E. arcuata
89’ Size variable, pronotum variable, but if arcuate, then lateral edges rounded…90
90 Luster shiny, elytral punctures usually large and in rows, outer protibial spur clearly larger than inner protibial spur…E. debilis
90’ Luster variable but usually not too shiny, punctures variable but rarely large, if protibial spurs disproportionate in size, then elytra with small punctures or tubercules…91
91 Longer protibial spur extending to almost to the third tarsomere…92 (E. rileyi)
91’ Longer protibial spur extending only to apex of the first tarsomere…93
92 Elytra shiny with prominent striae, Four Corners…E. rileyi reducta
92’ Elytra dull without very prominent striae, widespread…E. rileyi rileyi
93 “…longer protibial spur evenly tapering to a point from base to apex”…E. carbonaria (see Thomas 2012 for subspecies key)
93’ “…longer protibial spur parallel sided in basal half then tapering to a point at apex”…94
94 Elytral punctures irregular, San Francisco region…E. quadricollis
94’ Elytral punctures organized in rows, southeast Arizona…95 (E. anthracina)
95 Size larger, elytral punctures less fine, widespread…E. anthracina anthracina
95’ Size smaller, elytral punctures more fine, Chiricahua Mountains…E. anthracina lustrans

I plan for this to be the final update to this key before Eleodes gets officially split, I went through every statement and improved every one I could, as stated in the previous version V2.6, every species (excluding Blapylis) has been added. Let me know if you think it needs another update. More info in my profile: https://www.inaturalist.org/people/6449260

1 Mesofemora and metafemora dentate or subdentate...2
1’ Mesofemora and metafemora never dentate...4
2 Elytral punctures strongly muricate, elytra noticeably rough, spines on femora small or medium sized, pronotum widest at middle, Baja California...E. moesta
2’ Elytral punctures simple or slightly muricate, elytra appearing smooth, femoral spines variable, pronotum variable, widespread...3
3 Pronotum widest anterior of middle, femoral spines large, widespread...E. armata
3’ Pronotum widest at middle, femoral spines small to medium sized, Baja California...E. femorata
4 Body small, pronotum generally cordate and constricted at base, elytra apex not attenuate or caudate, roughly sculptured, never sulcate, sometimes with short setae, usually distributed across beaches, forests, and mountains, rarely in arid regions...subgenus Blapylis
4’ Body small or large, pronotum usually not cordate although often slightly constricted at base, elytral apex attenuate, caudate or neither, roughly sculptured or not, sulcate or not, with setae or not, widespread across all environments...5
5 Legs long with unproportionately small body, robust or not, body often flattened if not robust, never sulcate, if legs not abnormally long, then body elongate and flattened...6
5’ Legs long or short but with body fairly proportionate, only rarely flattened, sulcate or not, if legs fairly long, then not with conspicuous setae, or a small, elongate, and flattened body...22
6 Body generally slender and flattened, pronotal and elytral sculpturing simple (except in E. nigrina), never with conspicuous setae...7
6’ Body, generally robust, never flattened, pronotal and elytral sculpturing complex, usually with conspicuous setae...18
7 Elytral sculpturing muricate or scabrous, southern New Mexico to Canada, Sierra Nevada Mountains to Rocky Mountains...E. nigrina (in part)
7’ Elytral sculpturing simple, always below the northernmost edge of Colorado’s border...8
8 Range only in Inyo White Mountains...9
8’ Range widespread...10
9 Profemora with blunt tooth, anterolateral angles of pronotum blunt but projected, legs shorter...E. aalbui
9’ Profemora only sinuate, anterolateral angles of pronotum slightly projected, legs longer...E. microps
10 Range near Big Bend National Park and the Guadalupe Mountains...11
10’ Range in the Southwest United States excluding Texas and the Guadalupe Mountains...13
11 Range in the Guadalupe Mountains...E. guadalupensis
11’ Range near Big Bend National Park...12
12 Mentum with finger-like process, pronotum lacking projected anterolateral angles, widest at middle, near Rio Grande river...E. labialis
12’ Mentum without finger-like process, pronotum with slightly projected anterolateral angles, Big Bend National Park...E. easterlai
13 Range in the Mohave and Colorado Deserts of California, pronotum usually evenly arcuate, strial punctures larger than those of intervals...E. californica
13’ Range in Arizona, Utah, and the Colorado Desert, pronotum rarely evenly arcuate, strial punctures variable, but if in the Colorado Desert then those of striae and intervals small and subequal in size...14
14 Range in the Sonoran Desert or the most western portion of the Arizona-Utah border...15
14’ Range in the Sky Islands or the Colorado Plateau...16
15 Anterolateral angles strongly projected, caves by the most western point of the Arizona-Utah border…E. wynnei
15’ Anterolateral angles not strongly projected, the Sonoran Desert including the Colorado Desert…E. delicata (E. nevadensis)
16 Body elongate, northern Arizona and southern Utah...17
16’ Body not elongate, Sky Islands in southeast Arizona...E. dissimilis
17 Strial punctures larger than punctures of intervals, anterolateral edge of pronotum truncate, restricted to the Grand Canyon...E. leptoscelis
17’ Strial punctures subequal to punctures of intervals, anterolateral edge of pronotum not truncate, or only slightly truncate, northern Arizona and southern Utah...E. wheeleri
18 Large tubercles present on Elytra...19
18’ Elytra without large tubercules...20
19 Range in southern California to Oregon...E. granosa
19’ Range near the Four Corners...E. leechi
20 Pronotum evenly tuberculate, Oregon...E. spoliata
20’ Pronotum punctate, widespread...21
21 Antennas robust, body generally more robust...E. hirsuta
21’ Antennas thin, body generally more slender...E. pilosa
22 Size small or sometimes medium, covered in long setae, restricted to coastal and sometimes inland California, and Baja California, or rarely in the direction of and in Reno, or the Sonoran Desert...23
22’ Size small or large, usually glabrous, if with conspicuous setae then not found in coastal California, nor in Baja California, or the Sonoran Desert, and if found near Reno, Nevada, then third antennomere not shortened...28
23 Males with dentate profemora and elytra caudate, Sonoran Desert...E. tribulus
23’ Males nor females ever caudate or attenuate, coastal California and Baja California...24
24 Third antennomere shortened, body smaller and more slender, pill shaped, coastal California and towards and into Reno, Nevada...E. littoralis
24’ Third antennomere not shorted, body larger, California...25
25 Size 13mm or more...26
25’ Size 12mm or less...27
26 Setae orange, California and Baja California...E. osculans
26’ Setae black or grey, Baja California...E. ursus
27 Setae black, California and Baja California...E. nigropilosa
27’ Setae yellow, Baja California...E. subdeplanata
28 Elytra caudate at least in males and strongly muricate, near Tamaulipas if not caudate, size usually large...29
28’ Elytra caudate or not, but if caudate and muricately punctured then elytra only slightly muricate, elytra can be strongly muricate if not caudate and not near Tamaulipas, size large or small...31
29 Only males caudate with profemora dentate, Tamaulipas...E. fiski
29’ Both males and females caudate with mutic profemora, Four Corners and Sierra Nevada region...30
30 Elytra lacking long setae, Four Corners...E. caudifera
30’ Elytra always with long setae, Sierra Nevada region...E. longipilosa
31 Elytral sculpture very rough, elytra always attenuate but never caudate, pronotum wide, restricted to California, or slightly into Nevada and Oregon...32
31’ Elytral sculpture variable but if rough then elytra never attenuate and pronotum never wide, widespread...33
32 Luster shiny and elytral apex acutely attenuate, Pacific coast...E. marginata
32’ Luster dull and elytral apex blunt yet still attenuate, Sierra Nevada Mountains...E. scabricula (E. acutangula)
33 Body oval shaped, coated in minute setae, coastal Texas and Louisiana...E. veterator
33’ Body shape variable, if small and shaped slightly oval then not found in coastal Texas or Louisiana...34
34 Body small and fusiform...35
34’ Body small or large, shape variable but usually not fusiform...37
35 Elytra carinate, covered in minute setae...E. opaca
35’ Elytra lacking carina, glabrous...36
36 Body more fusiform, central and southern Great Plains...E. fusiformis
36’ Body less fusiform, the Sierra Nevadas to the Rocky Mountains, and the Arizona Sky Islands to British Colombia, northern Great Plains...E. extricata (in part)
37 Size medium to large, elytra usually inflated, wide, and large or sometimes flattened, especially in E. striolata, punctures either large, or appearing absent, although if elytra are not inflated, and attenuate, then punctures may be numerous and conspicuous, never sulcate...38
37’ Size variable but abdomen rarely inflated, if so, then punctures are small but conspicuous, sulcate or not...42
38 Elytral striae composed of large conspicuous punctures...E. goryi
38’ Elytral striae without large punctures...39
39 Elytra usually flattened, always attenuate, and heavily punctate, luster shiny, south and central Texas...E. striolata
39’ Elytra sometimes flattened, inconspicuous punctures present, although sometimes numerous and fairly noticeable, luster usually dull, Arizona, New Mexico, and Texas...40
40 Pronotum evenly arcuate and with anterolateral angles never projecting outwards, body grayish in color, covered in small punctures, Texas…E. spiculifera
40’ Pronotum parallel sided or evenly arcuate, anterolateral angles projecting outwards or not, color black, punctures inconspicuous, Arizona and New Mexico…41
41 Pronotum more or less parallel sided, anterolateral angles almost always projected outwards, prosternum forming large triangular wedge...E. subnitens
41’ Pronotum evenly arcuate, anterolateral angles only rarely projected outwards, prosternum not forming large triangular wedge...E. madrensis
42 Size almost always larger than 17mm, in rare cases reaching 14mm, but almost always with legs long, no matter the size, sometimes caudate...43
42’ Size almost always smaller than 17mm, if larger then legs almost always short, legs are often long if body in normal size range, never caudate...72
43 Body elongate, sometimes robust, pronotum not all that distinct from elytra, profemora never dentate and never with caudate elytra, punctures simple or muricate/scabrous, never sulcate...44
43’ Body fairly variable, sometimes elongate, often robust, pronotum usually quite distinct from elytra, males almost always with dentate profemora, elytra sometimes caudate, sulcate or not...49
44 Elytral punctures simple, anterolateral angles never very projected, body rarely flattened, but if so, then usually near the Sky Islands of southeast Arizona…46
44’ Elytral punctures not simple, anterolateral angles of pronotum projected, or body somewhat flattened and small, never in the Sky Islands…45
45 Anterolateral angles strongly projected, elytral punctures with tiny inconspicuous setae arising from each one, size usually not small...E. inornata
45’ Anterolateral angles not projected or only slightly projected, elytral punctures glabrous, size smaller, sometimes quite small…E. nigrina (continuation)
46 Elytra with red line running down the length of the elytra, this line never diffuses into black...E. ornatipennis
46’ Elytra entirely black, or if a red line is present along the elytra, it diffuses into black...47
47 Profemora strongly sinuate, pronotum widest slightly anterior of middle...E. hepburni
47’ Profemora simple, pronotum widest at middle...48
48 Prosternum horizontal, not projecting downwards, restricted to California...E. gigantea
48’ Prosternum projecting downwards, widespread but not found in California...E. longicollis
49 Elytra with carina, if carina absent and the elytra either sulcate or with numerous irregular punctures, then anterolateral angles of the pronotum rounded off and the pronotum widest anterior of middle, pronotum concave or convex...50
49’ Elytra lacking carina, if elytra sulcate or with numerous irregular punctures, then anterolateral angles of the pronotum acute, or if angles not acute then pronotum widest at middle, pronotum convex...55
50 Pronotum concave...E. suturalis
50’ Pronotum convex...51
51 Elytra with carina...E. acuta
51’ Elytra without carina...52 (E. obscura)
52 Elytra sulcate...53
52’ Elytra not sulcate...54
53 Elytra deeply sulcate, west of the Great Plains...E. obscura sulcipennis
53’ Elytra slightly sulcate, Great Plains...E. obscura obscura
54 Elytra with simple punctures, western Texas and southern New Mexico...E. obscura glabrisulca
54’ Elytra with muricate punctures, Four Corners...E. obscura dispersa
55 Elytra with large glabrous costae, intervals minutely hirsute, often coated with white debris, males are caudate, females are sometimes slightly caudate, legs long...E. mirabilis
55’ Elytra variable but without costae, caudate or not...56
56 Pronotum usually wide, humeral angles of elytra obsolete, never attenuate...E. grandicollis
56’ Pronotum variable, if wide, then elytral apex attenuate at least, humeral angles of elytra not obsolete...57
57 Restricted to California and Baja California, never having deep sulci, if not in California then tibia strongly curved and profemoral spine small and blunt and in Nevada or northwest Arizona...58
57’ Widespread, not found in California or Baja California, if found in California then elytra sulcate, never in Nevada or northwest Arizona unless elytra sulcate...64
58 Pronotum two or more times wider than the head...E. acuticauda
58’ Pronotum less then two times wider than the head...59
59 Pronotum more or less parallel sided, widest at middle, Mohave and Colorado Deserts, Nevada and Arizona...60
59’ Pronotum not parallel sided, or if so then elytral apex with groove in between both elytra, if in the Mohave or Colorado Desert then pronotum widest anterior of middle…61
60 Tibia strongly curved, profemoral spines blunt, never caudate...E. subcylindrica
60’ Tibia not strongly curved, profemoral spines acute, males caudate...E. mexicana
61 Elytral punctures minute, pronotum nearly parallel sided, although sometimes slightly arcuate, elytral apex with groove in between both elytra, Baja California…E. discincta
61’ Elytral punctures not minute, or if so then pronotum wide…62
62 Pronotum larger, elytral striae less prominent, widespread across California but absent in the most southernmost parts of California…E. dentipes
62’ Pronotum smaller, elytral striae more prominent, southern California…63
63 Pronotum widest anterior of middle, luster more shiny, elytra with simple punctures, glabrous, striae very clear, mainland southern California…E. gracilis distans
63’ Pronotum widest at middle, luster more dull, elytra with muricate punctures and conspicuous setae, striae not clearly defined, Channel Islands…E. adumbrata
64 Elytra strongly sulcate, at least on elytral apex…65
64’ Elytra not strongly sulcate…66
65 Pronotum widest anterior to middle, anterolateral angles of pronotum acute, widespread…E. hispilabris
65’ Pronotum widest at middle, anterolateral angles of pronotum rounded off, Texas…E. composita
66 Body flattened, elytra and pronotum not too distinctly separated, or if so then elytra remain wide up until their humeral angles, Texas…E. knullorum
66’ Body usually not flat, elytra and pronotum clearly separate, if elytra remain wide up until their humeral angles, then elytra inflated, widespread…67
67 Elytra strongly muricate, never caudate…E. sponsa
67’ Elytra with simple punctures or only slightly muricate, mainly at the elytral apex…68
68 Anterolateral angles of pronotum facing straight forward or only slightly projected outwards, males caudate and with the metatibia sinuate, southern Arizona…E. eschscholtzii eschscholtzii
68’ If in southern Arizona then anterolateral angles of pronotum projecting outwards, or hind angles of pronotum appearing quite rounded…69
69 Hind angles of pronotum appearing rounded, size large, elytra often inflated and strongly convex, or fairly parallel sided…70 (E. spinipes)
69’ Hind angles of pronotum not rounded or only slightly rounded, size medium to large, elytra never inflated, but often parallel sided…71
70 Elytra more or less parallel sided, west of the Pecos River…E. spinipes macrura
70’ Elytra ventricose, east of the Pecos River…E. spinipes ventricosa
71 Elytra caudate or strongly attenuate, El Paso region…E. tenuipes
71’ Elytra at most slightly attenuate…E. gracilis gracilis
72 Elytra with conspicuous setae…73
72’ Elytra glabrous, or only with short inconspicuous setae…77
73 Size less than 12mm, elytra shiny with complex sculpturing, and covered in golden hairs, areas with sandy soils generally around the Four Corners…E. barbata
73’ Size usually small but rarely less than 12mm, elytra usually dull, sometimes shiny, never with golden hairs, usually in deserts above the Sonoran Desert…74
74 Size larger, body more robust, northern Arizona and southern Utah…E. halli
74’ Size smaller, body more slender, generally around the Great Basin or the Great Sand Dunes of Colorado…75
75 Distributed only in the Great Sand Dunes National Park…E. hirtipennis
75’ Distributed generally around the Great Basin…76
76 Setae black, generally around the Great Basin…E. letcheri
76’ Setae brownish, in and around Utah…E. aspera
77 Elytra flat and widened, about the same width as pronotum, sides sometimes slightly rounded or with carina…78
77’ Sides of elytra rounded evenly, generally elongate or circular…82
78 Body covered with minute setae, usually appearing grey in color…E. tricostata
78’ Body glabrous…79
79 Elytral sculpturing rough, striae vague to absent, luster generally dull…E. neomexicana
79’ Elytra with clear striae, luster shiny…80
80 Elytra with deeply impressed striae…E. pedinoides
80’ Elytra with slightly impressed striae…80 (E. wenzeli)
81 Punctures of elytra fine but easily noticeable…E. wenzeli speculicollis
81’ Punctures of elytra extremely fine and minute…E. wenzeli wenzeli
82 Both elytra with at least three large smooth costae, legs often dark red, southern Utah…E. parowana
82’ Both elytra without at least three large costae…83
83 Size small, elytral luster generally shiny, elytra only with conspicuous irregular punctures, never with tubercules…E. extricata (continuation)
83’ Size small to medium, luster variable although generally dull if elytra with irregular punctures, said irregular punctures also smaller, elytra with punctures in rows or irregular, or with tubercules, papillae, or rugae…84
84 Elytra generally inflated, if not, then elytra more or less parallel sided, usually tuberculate, larger protibial spur extending almost to third tarsomere, Pacific Northwest…E. humeralis
84’ Elytra inflated or not, but if with tubercules then elytra not inflated and not parallel sided, if without tubercules then not found in the Pacific Northwest, or if in the Pacific Northwest then pronotum not clearly widest in front of middle…85
85 Elytra with papillae, pronotum wide, luster dull, California…E. papillosa
85’ Elytra without papillae, luster variable…86
86 Elytra with coarse transverse tuberculate rugae, luster shiny…E. corvina
86’ Elytra without coarse transverse rugae, tuberculate or not, luster variable…87
87 Elytra with large tubercules…88
87’ Elytra without large tubercules…89
88 Pronotum more or less arcuate and wider than long…E. granulata
88’ Pronotum more or less parallel sided and longer than wide…E. subtuberculata
89 Size small, pronotum evenly arcuate, lateral edges angular instead of rounded, punctures minute…E. arcuata
89’ Size variable, pronotum variable, but if arcuate, then lateral edges rounded…90
90 Luster shiny, elytral punctures usually large and in rows, outer protibial spur clearly larger than inner protibial spur…E. debilis
90’ Luster variable but usually not too shiny, punctures variable but rarely large, if protibial spurs disproportionate in size, then elytra with small punctures or tubercules…91
91 Longer protibial spur extending to almost to the third tarsomere…92 (E. rileyi)
91’ Longer protibial spur extending only to apex of the first tarsomere…93
92 Elytra shiny with prominent striae, Four Corners…E. rileyi reducta
92’ Elytra dull without very prominent striae, widespread…E. rileyi rileyi
93 “…longer protibial spur evenly tapering to a point from base to apex”…E. carbonaria (see Thomas 2012 for subspecies key)
93’ “…longer protibial spur parallel sided in basal half then tapering to a point at apex”…94
94 Elytral punctures irregular, San Francisco region…E. quadricollis
94’ Elytral punctures organized in rows, southeast Arizona…95 (E. anthracina)
95 Size larger, elytral punctures less fine, widespread…E. anthracina anthracina
95’ Size smaller, elytral punctures more fine, Chiricahua Mountains…E. anthracina lustrans

I do believe this will be the final update until the Eleodes split, finally to 100 couplets, now due to the addition of the subspecies of E. carbonaria, which I’ve suddenly become more interested in. I will say, and this is especially the case for E. carbonaria, subspecies keys may not always work properly, usually due to hybrids. More info in my profile: https://www.inaturalist.org/people/6449260

1 Mesofemora and metafemora dentate or subdentate...2
1’ Mesofemora and metafemora never dentate...4
2 Elytral punctures strongly muricate, elytra noticeably rough, spines on femora small or medium sized, pronotum widest at middle, Baja California...E. moesta
2’ Elytral punctures simple or slightly muricate, elytra appearing smooth, femoral spines variable, pronotum variable, widespread...3
3 Pronotum widest anterior of middle, femoral spines large, widespread...E. armata
3’ Pronotum widest at middle, femoral spines small to medium sized, Baja California...E. femorata
4 Body small, pronotum generally cordate and constricted at base, elytra apex not attenuate or caudate, roughly sculptured, never sulcate, sometimes with short setae, usually distributed across beaches, forests, and mountains, rarely in arid regions...subgenus Blapylis
4’ Body small or large, pronotum usually not cordate although often slightly constricted at base, elytral apex attenuate, caudate or neither, roughly sculptured or not, sulcate or not, with setae or not, widespread across all environments...5
5 Legs long with unproportionately small body, robust or not, body often flattened if not robust, never sulcate, if legs not abnormally long, then body elongate and flattened...6
5’ Legs long or short but with body fairly proportionate, only rarely flattened, sulcate or not, if legs fairly long, then not with conspicuous setae, or a small, elongate, and flattened body...22
6 Body generally slender and flattened, pronotal and elytral sculpturing simple (except in E. nigrina), never with conspicuous setae...7
6’ Body, generally robust, never flattened, pronotal and elytral sculpturing complex, usually with conspicuous setae...18
7 Elytral sculpturing muricate or scabrous, southern New Mexico to Canada, Sierra Nevada Mountains to Rocky Mountains...E. nigrina (in part)
7’ Elytral sculpturing simple, always below the northernmost edge of Colorado’s border...8
8 Range only in Inyo White Mountains...9
8’ Range widespread...10
9 Profemora with blunt tooth, anterolateral angles of pronotum blunt but projected, legs shorter...E. aalbui
9’ Profemora only sinuate, anterolateral angles of pronotum slightly projected, legs longer...E. microps
10 Range near Big Bend National Park and the Guadalupe Mountains...11
10’ Range in the Southwest United States excluding Texas and the Guadalupe Mountains...13
11 Range in the Guadalupe Mountains...E. guadalupensis
11’ Range near Big Bend National Park...12
12 Mentum with finger-like process, pronotum lacking projected anterolateral angles, widest at middle, near Rio Grande river...E. labialis
12’ Mentum without finger-like process, pronotum with slightly projected anterolateral angles, Big Bend National Park...E. easterlai
13 Range in the Mohave and Colorado Deserts of California, pronotum usually evenly arcuate, strial punctures larger than those of intervals...E. californica
13’ Range in Arizona, Utah, and the Colorado Desert, pronotum rarely evenly arcuate, strial punctures variable, but if in the Colorado Desert then those of striae and intervals small and subequal in size...14
14 Range in the Sonoran Desert or the most western portion of the Arizona-Utah border...15
14’ Range in the Sky Islands or the Colorado Plateau...16
15 Anterolateral angles strongly projected, caves by the most western point of the Arizona-Utah border…E. wynnei
15’ Anterolateral angles not strongly projected, the Sonoran Desert including the Colorado Desert…E. delicata (E. nevadensis)
16 Body elongate, northern Arizona and southern Utah...17
16’ Body not elongate, Sky Islands in southeast Arizona...E. dissimilis
17 Strial punctures larger than punctures of intervals, anterolateral edge of pronotum truncate, restricted to the Grand Canyon...E. leptoscelis
17’ Strial punctures subequal to punctures of intervals, anterolateral edge of pronotum not truncate, or only slightly truncate, northern Arizona and southern Utah...E. wheeleri
18 Large tubercles present on Elytra...19
18’ Elytra without large tubercules...20
19 Range in southern California to Oregon...E. granosa
19’ Range near the Four Corners...E. leechi
20 Pronotum evenly tuberculate, Oregon...E. spoliata
20’ Pronotum punctate, widespread...21
21 Antennas robust, body generally more robust...E. hirsuta
21’ Antennas thin, body generally more slender...E. pilosa
22 Size small or sometimes medium, covered in long setae, restricted to coastal and sometimes inland California, and Baja California, or rarely in the direction of and in Reno, or the Sonoran Desert...23
22’ Size small or large, usually glabrous, if with conspicuous setae then not found in coastal California, nor in Baja California, or the Sonoran Desert, and if found near Reno, Nevada, then third antennomere not shortened...28
23 Males with dentate profemora and elytra caudate, Sonoran Desert...E. tribulus
23’ Males nor females ever caudate or attenuate, coastal California and Baja California...24
24 Third antennomere shortened, body smaller and more slender, pill shaped, coastal California and towards and into Reno, Nevada...E. littoralis
24’ Third antennomere not shorted, body larger, California...25
25 Size 13mm or more...26
25’ Size 12mm or less...27
26 Setae orange, California and Baja California...E. osculans
26’ Setae black or grey, Baja California...E. ursus
27 Setae black, California and Baja California...E. nigropilosa
27’ Setae yellow, Baja California...E. subdeplanata
28 Elytra caudate at least in males and strongly muricate, near Tamaulipas if not caudate, size usually large...29
28’ Elytra caudate or not, but if caudate and muricately punctured then elytra only slightly muricate, elytra can be strongly muricate if not caudate and not near Tamaulipas, size large or small...31
29 Only males caudate with profemora dentate, Tamaulipas...E. fiski
29’ Both males and females caudate with mutic profemora, Four Corners and Sierra Nevada region...30
30 Elytra lacking long setae, Four Corners...E. caudifera
30’ Elytra always with long setae, Sierra Nevada region...E. longipilosa
31 Elytral sculpture very rough, elytra always attenuate but never caudate, pronotum wide, restricted to California, or slightly into Nevada and Oregon...32
31’ Elytral sculpture variable but if rough then elytra never attenuate and pronotum never wide, widespread...33
32 Luster shiny and elytral apex acutely attenuate, Pacific coast...E. marginata
32’ Luster dull and elytral apex blunt yet still attenuate, Sierra Nevada Mountains...E. scabricula (E. acutangula)
33 Body oval shaped, coated in minute setae, coastal Texas and Louisiana...E. veterator
33’ Body shape variable, if small and shaped slightly oval then not found in coastal Texas or Louisiana...34
34 Body small and fusiform...35
34’ Body small or large, shape variable but usually not fusiform...37
35 Elytra carinate, covered in minute setae...E. opaca
35’ Elytra lacking carina, glabrous...36
36 Body more fusiform, central and southern Great Plains...E. fusiformis
36’ Body less fusiform, the Sierra Nevadas to the Rocky Mountains, and the Arizona Sky Islands to British Colombia, northern Great Plains...E. extricata (in part)
37 Size medium to large, elytra usually inflated, wide, and large or sometimes flattened, especially in E. striolata, punctures either large, or appearing absent, although if elytra are not inflated, and attenuate, then punctures may be numerous and conspicuous, never sulcate...38
37’ Size variable but abdomen rarely inflated, if so, then punctures are small but conspicuous, sulcate or not...42
38 Elytral striae composed of large conspicuous punctures...E. goryi
38’ Elytral striae without large punctures...39
39 Elytra usually flattened, always attenuate, and heavily punctate, luster shiny, south and central Texas...E. striolata
39’ Elytra sometimes flattened, inconspicuous punctures present, although sometimes numerous and fairly noticeable, luster usually dull, Arizona, New Mexico, and Texas...40
40 Pronotum evenly arcuate and with anterolateral angles never projecting outwards, body grayish in color, covered in small punctures, Texas…E. spiculifera
40’ Pronotum parallel sided or evenly arcuate, anterolateral angles projecting outwards or not, color black, punctures inconspicuous, Arizona and New Mexico…41
41 Pronotum more or less parallel sided, anterolateral angles almost always projected outwards, prosternum forming large triangular wedge...E. subnitens
41’ Pronotum evenly arcuate, anterolateral angles only rarely projected outwards, prosternum not forming large triangular wedge...E. madrensis
42 Size almost always larger than 17mm, in rare cases reaching 14mm, but almost always with legs long, no matter the size, sometimes caudate...43
42’ Size almost always smaller than 17mm, if larger then legs almost always short, unless body is fusiform, legs are often long if body in normal size range, never caudate...72
43 Body elongate, sometimes robust, pronotum not all that distinct from elytra, profemora never dentate and never with caudate elytra, punctures simple or muricate/scabrous, never sulcate...44
43’ Body fairly variable, sometimes elongate, often robust, pronotum usually quite distinct from elytra, males almost always with dentate profemora, elytra sometimes caudate, sulcate or not...49
44 Elytral punctures simple, anterolateral angles never very projected, body rarely flattened, but if so, then usually near the Sky Islands of southeast Arizona…46
44’ Elytral punctures not simple, anterolateral angles of pronotum projected, or body somewhat flattened and small, never in the Sky Islands…45
45 Anterolateral angles strongly projected, elytral punctures with tiny inconspicuous setae arising from each one, size usually not small...E. inornata
45’ Anterolateral angles not projected or only slightly projected, elytral punctures glabrous, size smaller, sometimes quite small…E. nigrina (continuation)
46 Elytra with red line running down the length of the elytra, this line never diffuses into black...E. ornatipennis
46’ Elytra entirely black, or if a red line is present along the elytra, it diffuses into black...47
47 Profemora strongly sinuate, pronotum widest slightly anterior of middle...E. hepburni
47’ Profemora simple, pronotum widest at middle...48
48 Prosternum horizontal, not projecting downwards, restricted to California...E. gigantea
48’ Prosternum projecting downwards, widespread but not found in California...E. longicollis
49 Elytra with carina, if carina absent and the elytra either sulcate or with numerous irregular punctures, then anterolateral angles of the pronotum rounded off and the pronotum widest anterior of middle, pronotum concave or convex...50
49’ Elytra lacking carina, if elytra sulcate or with numerous irregular punctures, then anterolateral angles of the pronotum acute, or if angles not acute then pronotum widest at middle, pronotum convex...55
50 Pronotum concave...E. suturalis
50’ Pronotum convex...51
51 Elytra with carina...E. acuta
51’ Elytra without carina...52 (E. obscura)
52 Elytra sulcate...53
52’ Elytra not sulcate...54
53 Elytra deeply sulcate, west of the Great Plains...E. obscura sulcipennis
53’ Elytra slightly sulcate, Great Plains...E. obscura obscura
54 Elytra with simple punctures, western Texas and southern New Mexico...E. obscura glabrisulca
54’ Elytra with muricate punctures, Four Corners...E. obscura dispersa
55 Elytra with large glabrous costae, intervals minutely hirsute, often coated with white debris, males are caudate, females are sometimes slightly caudate, legs long...E. mirabilis
55’ Elytra variable but without costae, caudate or not...56
56 Pronotum usually wide, humeral angles of elytra obsolete, never attenuate...E. grandicollis
56’ Pronotum variable, if wide, then elytral apex attenuate at least, humeral angles of elytra not obsolete...57
57 Restricted to California and Baja California, never having deep sulci, if not in California then tibia strongly curved and profemoral spine small and blunt and in Nevada or northwest Arizona...58
57’ Widespread, not found in California or Baja California, if found in California then elytra sulcate, never in Nevada or northwest Arizona unless elytra sulcate...64
58 Pronotum two or more times wider than the head...E. acuticauda
58’ Pronotum less then two times wider than the head...59
59 Pronotum more or less parallel sided, widest at middle, Mohave and Colorado Deserts, Nevada and Arizona...60
59’ Pronotum not parallel sided, or if so then elytral apex with groove in between both elytra, if in the Mohave or Colorado Desert then pronotum widest anterior of middle…61
60 Tibia strongly curved, profemoral spines blunt, never caudate...E. subcylindrica
60’ Tibia not strongly curved, profemoral spines acute, males caudate...E. mexicana
61 Elytral punctures minute, pronotum nearly parallel sided, although sometimes slightly arcuate, elytral apex with groove in between both elytra, Baja California…E. discincta
61’ Elytral punctures not minute, or if so then pronotum wide…62
62 Pronotum larger, elytral striae less prominent, widespread across California but absent in the most southernmost parts of California…E. dentipes
62’ Pronotum smaller, elytral striae more prominent, southern California…63
63 Pronotum widest anterior of middle, luster more shiny, elytra with simple punctures, glabrous, striae very clear, mainland southern California…E. gracilis distans
63’ Pronotum widest at middle, luster more dull, elytra with muricate punctures and conspicuous setae, striae not clearly defined, Channel Islands…E. adumbrata
64 Elytra strongly sulcate, at least on elytral apex…65
64’ Elytra not strongly sulcate…66
65 Pronotum widest anterior to middle, anterolateral angles of pronotum acute, widespread…E. hispilabris
65’ Pronotum widest at middle, anterolateral angles of pronotum rounded off, Texas…E. composita
66 Body flattened, elytra and pronotum not too distinctly separated, or if so then elytra remain wide up until their humeral angles, Texas…E. knullorum
66’ Body usually not flat, elytra and pronotum clearly separate, if elytra remain wide up until their humeral angles, then elytra inflated, widespread…67
67 Elytra strongly muricate, never caudate…E. sponsa
67’ Elytra with simple punctures or only slightly muricate, mainly at the elytral apex…68
68 Anterolateral angles of pronotum facing straight forward or only slightly projected outwards, males caudate and with the metatibia sinuate, southern Arizona…E. eschscholtzii eschscholtzii
68’ If in southern Arizona then anterolateral angles of pronotum projecting outwards, or hind angles of pronotum appearing quite rounded…69
69 Hind angles of pronotum appearing rounded, size large, elytra often inflated and strongly convex, or fairly parallel sided…70 (E. spinipes)
69’ Hind angles of pronotum not rounded or only slightly rounded, size medium to large, elytra never inflated, but often parallel sided…71
70 Elytra more or less parallel sided, west of the Pecos River…E. spinipes macrura
70’ Elytra ventricose, east of the Pecos River…E. spinipes ventricosa
71 Elytra caudate or strongly attenuate, El Paso region…E. tenuipes
71’ Elytra at most slightly attenuate…E. gracilis gracilis
72 Elytra with conspicuous setae…73
72’ Elytra glabrous, or only with short inconspicuous setae…77
73 Size less than 12mm, elytra shiny with complex sculpturing, and covered in golden hairs, areas with sandy soils generally around the Four Corners…E. barbata
73’ Size usually small but rarely less than 12mm, elytra usually dull, sometimes shiny, never with golden hairs, usually in deserts above the Sonoran Desert…74
74 Size larger, body more robust, northern Arizona and southern Utah…E. halli
74’ Size smaller, body more slender, generally around the Great Basin or the Great Sand Dunes of Colorado…75
75 Distributed only in the Great Sand Dunes National Park…E. hirtipennis
75’ Distributed generally around the Great Basin…76
76 Setae black, generally around the Great Basin…E. letcheri
76’ Setae brownish, in and around Utah…E. aspera
77 Elytra flat and widened, about the same width as pronotum, sides sometimes slightly rounded or with carina…78
77’ Sides of elytra rounded evenly, generally elongate or circular…82
78 Body covered with minute setae, usually appearing grey in color…E. tricostata
78’ Body glabrous…79
79 Elytral sculpturing rough, striae vague to absent, luster generally dull…E. neomexicana
79’ Elytra with clear striae, luster shiny…80
80 Elytra with deeply impressed striae…E. pedinoides
80’ Elytra with slightly impressed striae…80 (E. wenzeli)
81 Punctures of elytra fine but easily noticeable…E. wenzeli speculicollis
81’ Punctures of elytra extremely fine and minute…E. wenzeli wenzeli
82 Both elytra with at least three large smooth costae, legs often dark red, southern Utah…E. parowana
82’ Both elytra without at least three large costae…83
83 Size small, elytral luster generally shiny, elytra only with conspicuous irregular punctures, never with tubercules…E. extricata (continuation)
83’ Size small to medium, luster variable although generally dull if elytra with irregular punctures, said irregular punctures also smaller, elytra with punctures in rows or irregular, or with tubercules, papillae, or rugae…84
84 Elytra generally inflated, if not, then elytra more or less parallel sided, usually tuberculate, larger protibial spur extending almost to third tarsomere, Pacific Northwest…E. humeralis
84’ Elytra inflated or not, but if with tubercules then elytra not inflated and not parallel sided, if without tubercules then not found in the Pacific Northwest, or if in the Pacific Northwest then pronotum not clearly widest in front of middle…85
85 Elytra with papillae, pronotum wide, luster dull, California…E. papillosa
85’ Elytra without papillae, luster variable…86
86 Elytra with coarse transverse tuberculate rugae, luster shiny…E. corvina
86’ Elytra without coarse transverse rugae, tuberculate or not, luster variable…87
87 Elytra with large tubercules…88
87’ Elytra without large tubercules…89
88 Pronotum more or less arcuate and wider than long…E. granulata
88’ Pronotum more or less parallel sided and longer than wide…E. subtuberculata
89 Size small, pronotum evenly arcuate, lateral edges angular instead of rounded, punctures minute…E. arcuata
89’ Size variable, pronotum variable, but if arcuate, then lateral edges rounded…90
90 Luster shiny, elytral punctures usually large and in rows, outer protibial spur clearly larger than inner protibial spur…E. debilis
90’ Luster variable but usually not too shiny, punctures variable but rarely large, if protibial spurs disproportionate in size, then elytra with small punctures or tubercules…91
91 Longer protibial spur extending to almost to the third tarsomere…92 (E. rileyi)
91’ Longer protibial spur extending only to apex of the first tarsomere…93
92 Elytra shiny with prominent striae, Four Corners…E. rileyi reducta
92’ Elytra dull without very prominent striae, widespread…E. rileyi rileyi
93 “…longer protibial spur parallel sided in basal half then tapering to a point at apex”…94
93’ “…longer protibial spur evenly tapering to a point from base to apex”…96 (E. carbonaria)
94 Elytral punctures irregular, San Francisco region…E. quadricollis
94’ Elytral punctures organized in rows, generally around southeast Arizona…95 (E. anthracina)
95 Size larger, elytral punctures less fine, widespread…E. anthracina anthracina
95’ Size smaller, elytral punctures more fine, Chiricahua Mountains…E. anthracina lustrans
96 Strial punctures and those of intervals subequal in size, often irregularly patterned, restricted to California…E. carbonaria omissa
96’ Punctures variable, but if in California then strial punctures larger than those of intervals and in rows…97
97 Body usually fairly fusiform, punctures conspicuous and in rows, east of the Pecos River and always below the southernmost edge of Arizona and New Mexico’s border…E. carbonaria soror
97’ Body only rarely fusiform, punctures variable, west of the Pecos River, or if not then above the southernmost edge of Arizona and New Mexico’s border…98
98 Punctures of elytra simple…100
98’ Punctures of elytra muricate…99
99 Strial punctures and those of intervals subequal in size, often irregularly patterned, generally around northwest New Mexico…E. carbonaria knausii
99’ Strial punctures larger than those of intervals, striae in rows, often in ridges, widespread…E. carbonaria obsoleta
100 Body usually more fusiform, size larger than 17mm, southern Arizona and New Mexico…E. carbonaria chihuahuaensis
100’ Body usually not fusiform, size 17mm or smaller, widespread…E. carbonaria carbonaria

I should definitely refrain from saying that an update won’t be the final one, but I believe this is nearly as good as this key can get. I have moved some things around, and added more details. I think it’s fitting that E. armata is the first species keyed out, with its reputation as one of the easiest species to ID, while E. carbonaria carbonaria is the last, as one of the most variable subspecies of E. carbonaria, often confused with E. debilis or other E. carbonaria subspecies, and various other vaguely similar species. More info in my profile: https://www.inaturalist.org/people/6449260

The key on Google Drive (looks nicer and can be saved): https://drive.google.com/file/d/1oWtrh5NuMuYoi9ruTAfPS-nqHMxTYrcN/view?usp=drivesdk

1 Mesofemora and metafemora dentate or subdentate...2
1’ Mesofemora and metafemora never dentate...4
2 Pronotum widest anterior of middle, elytra with simple punctures, widespread...E. armata
2’ Pronotum widest at middle, elytral punctures simple or muricate, Baja California...3
3 Elytra usually appearing rough, metatibia more or less straight...E. moesta
3’ Elytra appearing smooth, metatibia curved or bent...E. femorata
4 Body small, pronotum generally cordate and constricted at base, elytral apex not attenuate or caudate, roughly sculptured, never sulcate, sometimes with short setae, usually distributed across beaches, forests, and mountains, rarely in arid regions...subgenus Blapylis
4’ Body small or large, pronotum usually not cordate although often slightly constricted at base, elytral apex attenuate, caudate or neither, roughly sculptured or not, sulcate or not, with setae or not, widespread across all environments...5
5 Legs long with unproportionately small body, robust or not, body often flattened if not robust, never sulcate, if legs not abnormally long, then body elongate and flattened...6
5’ Legs long or short but with body fairly proportionate, only rarely flattened, sulcate or not, if legs fairly long, then not with conspicuous setae, or a small, elongate, and flattened body...22
6 Body generally slender and flattened, pronotal and elytral sculpturing simple (except in E. nigrina), never with conspicuous setae...7
6’ Body, generally robust, never flattened, pronotal and elytral sculpturing complex, usually with conspicuous setae...18
7 Elytral sculpturing muricate or scabrous, southern New Mexico to Canada, Sierra Nevada Mountains to Rocky Mountains...E. nigrina (in part)
7’ Elytral sculpturing simple, always below the northernmost edge of Colorado’s border...8
8 Range only in the Inyo White Mountains...9
8’ Range widespread but not in the Inyo White Mountains...10
9 Profemora with blunt tooth, anterolateral angles of pronotum blunt but projected, legs shorter...E. aalbui
9’ Profemora only sinuate, anterolateral angles of pronotum slightly projected, legs longer...E. microps
10 Range near western Texas and the Guadalupe Mountains...11
10’ Range in the Southwest United States excluding Texas and the Guadalupe Mountains...13
11 Probasitarsus with golden setae present, range in the Guadalupe Mountains...E. guadalupensis
11’ Probasitarsus lacking golden setae, only with orange spines, range near southwestern Texas...12
12 Mentum with finger-like process, pronotum lacking projected anterolateral angles, widest at middle, near Rio Grande river...E. labialis
12’ Mentum without finger-like process, pronotum with slightly projected anterolateral angles, Big Bend National Park...E. easterlai
13 Range in the Mohave and Colorado Deserts of California, pronotum usually evenly arcuate, strial punctures larger than those of intervals...E. californica
13’ Range in Arizona, Utah, and the Colorado Desert, pronotum rarely evenly arcuate, strial punctures variable, but if in the Colorado Desert then those of striae and intervals small and subequal in size...14
14 Range in the Sonoran Desert including the Colorado Desert or the most western portion of the Arizona-Utah border...15
14’ Range in the Sky Islands or the Colorado Plateau...16
15 Anterolateral angles strongly projected, caves by the most western point of the Arizona-Utah border…E. wynnei
15’ Anterolateral angles not strongly projected, the Sonoran Desert including the Colorado Desert…E. delicata (E. nevadensis)
16 Body elongate, northern Arizona and southern Utah...17
16’ Body not elongate, Sky Islands in southeast Arizona...E. dissimilis
17 Strial punctures larger than punctures of intervals, anterolateral edge of pronotum truncate, restricted to the Grand Canyon...E. leptoscelis
17’ Strial punctures subequal to punctures of intervals, anterolateral edge of pronotum not truncate, or only slightly truncate, northern Arizona and southern Utah...E. wheeleri
18 Large tubercles present on Elytra...19
18’ Elytra without large tubercules...20
19 Range in southern California to Oregon...E. granosa
19’ Range near the Four Corners...E. leechi
20 Pronotum evenly tuberculate, Oregon...E. spoliata
20’ Pronotum punctate, widespread...21
21 Antennas robust, body generally more robust...E. hirsuta
21’ Antennas thin, body generally more slender...E. pilosa
22 Size small or sometimes medium, covered in long setae, restricted to coastal and sometimes inland California, and Baja California, or rarely in the direction of and in Reno, or the Sonoran Desert...23
22’ Size small or large, usually glabrous, if with conspicuous setae then not found in coastal California, nor in Baja California, or the Sonoran Desert, and if found near Reno, Nevada, then third antennomere not shortened...28
23 Males with dentate profemora and elytra caudate, Sonoran Desert...E. tribulus
23’ Males nor females ever caudate or attenuate, coastal California and Baja California...24
24 Third antennomere shortened, body smaller and more slender, pill shaped, coastal California and towards and into Reno, Nevada...E. littoralis
24’ Third antennomere not shorted, body larger, California...25
25 Size 13mm or more...26
25’ Size 12mm or less...27
26 Setae orange, California and Baja California...E. osculans
26’ Setae black or grey, Baja California...E. ursus
27 Setae black, California and Baja California...E. nigropilosa
27’ Setae yellow, Baja California...E. subdeplanata
28 Elytra caudate at least in males and strongly muricate, near Tamaulipas if not caudate, size usually large...29
28’ Elytra caudate or not, but if caudate and muricately punctured then elytra only slightly muricate, elytra can be strongly muricate if not caudate and not near Tamaulipas, size large or small...31
29 Only males caudate with profemora dentate, Tamaulipas...E. fiski
29’ Both males and females caudate with mutic profemora, Four Corners and Sierra Nevada region...30
30 Elytra lacking long setae, Four Corners...E. caudifera
30’ Elytra always with long setae, Sierra Nevada region...E. longipilosa
31 Elytral sculpture very rough, elytra always attenuate but never caudate, pronotum wide, restricted to California, or slightly into Nevada and Oregon...32
31’ Elytral sculpture variable but if rough then elytra never attenuate and pronotum never wide, widespread...33
32 Luster shiny and elytral apex acutely attenuate, Pacific coast...E. marginata
32’ Luster dull and elytral apex blunt yet still attenuate, Sierra Nevada Mountains...E. scabricula (E. acutangula)
33 Body oval shaped, coated in minute setae, coastal Texas and Louisiana...E. veterator
33’ Body shape variable, if small and shaped slightly oval then not found in coastal Texas or Louisiana...34
34 Body small and fusiform, punctures usually small and scattered...35
34’ Body small or large, shape variable but usually not fusiform, if so, then punctures usually larger and in rows...37
35 Elytra carinate, covered in minute setae...E. opaca
35’ Elytra lacking carina, glabrous...36
36 Body more fusiform, central and southern Great Plains...E. fusiformis
36’ Body less fusiform, the Sierra Nevadas to the Rocky Mountains, and the Arizona Sky Islands to British Colombia, northern Great Plains...E. extricata (in part)
37 Size medium to large, elytra usually inflated, wide, and large or sometimes flattened, especially in E. striolata, punctures either large, or appearing absent, although if elytra are not inflated, and attenuate, then punctures may be numerous and conspicuous, never sulcate...38
37’ Size variable but abdomen rarely inflated, if so, then punctures are small but conspicuous, sulcate or not...42
38 Elytral striae composed of large conspicuous punctures...E. goryi
38’ Elytral striae without large punctures...39
39 Elytra usually flattened, always attenuate, and heavily punctate, luster shiny, south and central Texas...E. striolata
39’ Elytra sometimes flattened, inconspicuous punctures present, although sometimes numerous and fairly noticeable, luster usually dull, Arizona, New Mexico, and Texas...40
40 Pronotum evenly arcuate and with anterolateral angles never projecting outwards, body grayish in color, covered in small punctures, Texas…E. spiculifera
40’ Pronotum parallel sided or evenly arcuate, anterolateral angles projecting outwards or not, color black, punctures inconspicuous, Arizona and New Mexico…41
41 Pronotum more or less parallel sided, anterolateral angles almost always projected outwards, prosternum forming large triangular wedge...E. subnitens
41’ Pronotum evenly arcuate, anterolateral angles only rarely projected outwards, prosternum not forming large triangular wedge...E. madrensis
42 Size almost always larger than 17mm, in rare cases reaching 14mm, but almost always with legs long, no matter the size, sometimes caudate...43
42’ Size almost always smaller than 17mm, if larger then legs almost always short, unless body is fusiform, legs are often long if body in normal size range, never caudate...72
43 Body elongate, sometimes robust, pronotum not all that distinct from elytra, profemora never dentate and never with caudate elytra, punctures simple or muricate/scabrous, never sulcate...44
43’ Body fairly variable, sometimes elongate, often robust, pronotum usually quite distinct from elytra, males almost always with dentate profemora, elytra sometimes caudate, sulcate or not...49
44 Elytral punctures simple, anterolateral angles never very projected, body rarely flattened, but if so, then usually near the Sky Islands of southeast Arizona…46
44’ Elytral punctures not simple, anterolateral angles of pronotum projected, or body somewhat flattened and small, never in the Sky Islands…45
45 Anterolateral angles strongly projected, elytral punctures with tiny inconspicuous setae arising from each one, size usually not small...E. inornata
45’ Anterolateral angles not projected or only slightly projected, elytral punctures glabrous, size smaller, sometimes quite small…E. nigrina (continuation)
46 Elytra with red line running down the length of the elytra, this line never diffuses into black...E. ornatipennis
46’ Elytra entirely black, or if a red line is present along the elytra, it diffuses into black...47
47 Profemora strongly sinuate, pronotum widest slightly anterior of middle...E. hepburni
47’ Profemora simple, pronotum widest at middle...48
48 Prosternum smaller, only slightly projecting downwards, restricted to California...E. gigantea
48’ Prosternum larger prominently projecting downwards, widespread but not found in California...E. longicollis
49 Elytra with carina, if carina absent and the elytra either sulcate or with numerous irregular punctures, then anterolateral angles of the pronotum rounded off and the pronotum widest anterior of middle, pronotum concave or convex...50
49’ Elytra lacking carina, if elytra sulcate or with numerous irregular punctures, then anterolateral angles of the pronotum acute, or if angles not acute then pronotum widest at middle, pronotum convex...55
50 Pronotum concave...E. suturalis
50’ Pronotum convex...51
51 Elytra with carina...E. acuta
51’ Elytra without carina...52 (E. obscura)
52 Elytra with clear, prominent striae...53
52’ Elytra without clear, prominent striae...54
53 Elytra deeply sulcate, west of the Great Plains...E. obscura sulcipennis
53’ Elytra slightly sulcate, Great Plains...E. obscura obscura
54 Elytra with simple punctures, western Texas and southern New Mexico...E. obscura glabrisulca
54’ Elytra with muricate punctures, Four Corners...E. obscura dispersa
55 Elytra with large glabrous costae, intervals minutely hirsute, often coated with white debris, males are caudate, females are sometimes slightly caudate, legs long...E. mirabilis
55’ Elytra variable but without costae, caudate or not...56
56 Pronotum usually wide, humeral angles of elytra obsolete, never attenuate...E. grandicollis
56’ Pronotum variable, if wide, then elytral apex attenuate at least, humeral angles of elytra not obsolete...57
57 Elytra strongly sulcate, at least on elytral apex…58
57’ Elytra not strongly sulcate…59
58 Pronotum widest anterior to middle, anterolateral angles of pronotum acute, widespread…E. hispilabris
58’ Pronotum widest at middle, anterolateral angles of pronotum rounded off, Texas…E. composita
59 Restricted to California and Baja California, if not in California then tibia strongly curved, profemoral spine small and blunt, and in Nevada, northwest Arizona, or extreme southwest Utah...60
59’ Widespread, but not found in California, Baja California, Nevada, northwest Arizona, or Utah...66
60 Pronotum two or more times wider than the head...E. acuticauda
60’ Pronotum less then two times wider than the head...61
61 Pronotum more or less parallel sided, widest at middle, Mohave and Colorado Deserts, Nevada and Arizona...62
61’ Pronotum not parallel sided, or if so then elytral apex with groove in between both elytra, if in the Mohave or Colorado Desert then pronotum widest anterior of middle…63
62 Tibia strongly curved, profemoral spines blunt, never caudate...E. subcylindrica
62’ Tibia not strongly curved, profemoral spines acute, males caudate...E. mexicana
63 Elytral punctures minute, pronotum nearly parallel sided, although sometimes slightly arcuate, elytral apex with groove in between both elytra, Baja California…E. discincta
63’ Elytral punctures not minute, or if so then pronotum wide…64
64 Pronotum usually broad and strongly arcuate, elytral striae less prominent, widespread across California but absent in the most southernmost parts of California…E. dentipes
64’ Pronotum more narrow, less prominently arcuate, elytral striae more prominent, southern California…65
65 Pronotum widest anterior of middle, luster more shiny, elytra with simple punctures, glabrous, striae very clear, mainland southern California…E. gracilis distans
65’ Pronotum widest at middle, luster more dull, elytra with muricate punctures and conspicuous setae, striae not clearly defined, Channel Islands…E. adumbrata
66 Body flattened, elytra and pronotum not too distinctly separated, or if so then elytra remain wide up until their humeral angles, Texas…E. knullorum
66’ Body usually not flat, elytra and pronotum clearly separate, if elytra remain wide up until their humeral angles, then elytra inflated, widespread…67
67 Elytra strongly muricate, never caudate…E. sponsa
67’ Elytra with simple punctures or only slightly asperate, mainly at the elytral apex, usually caudate, at least in males…68
68 Anterolateral angles of pronotum facing straight forward or only slightly projected outwards, males caudate and with the metatibia sinuate, southern Arizona…E. eschscholtzii eschscholtzii
68’ If in southern Arizona then anterolateral angles of pronotum projecting outwards, or hind angles of pronotum appearing quite rounded…69
69 Hind angles of pronotum appearing rounded, size large, elytra often inflated and strongly convex, or fairly parallel sided…70 (E. spinipes)
69’ Hind angles of pronotum not rounded or only slightly rounded, size medium to large, elytra never inflated, but often parallel sided…71
70 Elytra more or less parallel sided, west of the Pecos River…E. spinipes macrura
70’ Elytra ventricose, east of the Pecos River…E. spinipes ventricosa
71 Elytra caudate or strongly attenuate, El Paso region…E. tenuipes
71’ Elytra at most slightly attenuate…E. gracilis gracilis
72 Elytra with conspicuous setae…73
72’ Elytra glabrous, or only with short inconspicuous setae…77
73 Size less than 12mm, elytra shiny with complex sculpturing, and covered in golden hairs, areas with sandy soils generally around the Four Corners…E. barbata
73’ Size usually small but rarely less than 12mm, elytra usually dull, sometimes shiny, never with golden hairs, usually in deserts above the Sonoran Desert…74
74 Size larger, body more robust, northern Arizona and southern Utah…E. halli
74’ Size smaller, body more slender, generally around the Great Basin or the Great Sand Dunes of Colorado…75
75 Distributed only in the Great Sand Dunes National Park…E. hirtipennis
75’ Distributed generally around the Great Basin…76
76 Setae black, generally around the Great Basin…E. letcheri
76’ Setae brownish, in and around Utah…E. aspera
77 Elytra flat and widened, about the same width as pronotum, sides sometimes slightly rounded or with carina…78
77’ Sides of elytra rounded evenly, generally elongate or circular…82
78 Body covered with minute setae, usually appearing grey in color…E. tricostata
78’ Body glabrous…79
79 Elytral sculpturing rough, striae vague to absent, luster generally dull…E. neomexicana
79’ Elytra with clear striae, luster shiny…80
80 Elytra with deeply impressed striae…E. pedinoides
80’ Elytra with slightly impressed striae…80 (E. wenzeli)
81 Punctures of elytra fine but easily noticeable…E. wenzeli speculicollis
81’ Punctures of elytra extremely fine and minute…E. wenzeli wenzeli
82 Both elytra with at least three large smooth costae, legs often dark red, southern Utah…E. parowana
82’ Both elytra without at least three large costae…83
83 Size small, elytral luster generally shiny, elytra only with conspicuous irregular punctures, never with tubercules…E. extricata (continuation)
83’ Size small to medium, luster variable although generally dull if elytra with irregular punctures, said irregular punctures also smaller, elytra with punctures in rows or irregular, or with tubercules, papillae, or rugae…84
84 Elytra generally inflated, if not, then elytra more or less parallel sided, usually tuberculate, larger protibial spur extending almost to third tarsomere, Pacific Northwest…E. humeralis
84’ Elytra inflated or not, but if with tubercules then elytra not inflated and not parallel sided, if without tubercules then not found in the Pacific Northwest, or if in the Pacific Northwest then pronotum not clearly widest in front of middle…85
85 Elytra with papillae, pronotum wide, luster dull, California…E. papillosa
85’ Elytra without papillae, luster variable…86
86 Elytra with coarse transverse tuberculate rugae, luster shiny…E. corvina
86’ Elytra without coarse transverse rugae, tuberculate or not, luster variable…87
87 Elytra with large tubercules…88
87’ Elytra without large tubercules…89
88 Pronotum more or less arcuate and wider than long…E. granulata
88’ Pronotum more or less parallel sided and longer than wide…E. subtuberculata
89 Size small, pronotum evenly arcuate, punctures minute, body generally fairly short, Arizona and New Mexico…E. arcuata
89’ Size variable, pronotum variable, but if evenly arcuate, then punctures more conspicuous…90
90 Luster shiny, elytral punctures usually fairly large and in rows, outer protibial spur clearly larger than inner protibial spur…E. debilis
90’ Luster variable but usually not too shiny, punctures variable but rarely large, if protibial spurs disproportionate in size, then elytra with small punctures or tubercules and or luster more dull…91
91 Longer protibial spur extending to almost to the third tarsomere…92 (E. rileyi)
91’ Longer protibial spur extending only to apex of the first tarsomere…93
92 Elytra shiny with prominent striae, Four Corners…E. rileyi reducta
92’ Elytra dull without very prominent striae, widespread…E. rileyi rileyi
93 “…longer protibial spur parallel sided in basal half then tapering to a point at apex”…94
93’ “…longer protibial spur evenly tapering to a point from base to apex”…96 (E. carbonaria)
94 Elytral punctures irregular, San Francisco region…E. quadricollis
94’ Elytral punctures organized in rows, generally around southeast Arizona…95 (E. anthracina)
95 Size larger, elytral punctures less fine, widespread…E. anthracina anthracina
95’ Size smaller, elytral punctures more fine, Chiricahua Mountains…E. anthracina lustrans
96 Strial punctures and those of intervals subequal in size, often irregularly patterned, restricted to California…E. carbonaria omissa
96’ Punctures variable, but if in California then strial punctures larger than those of intervals and in rows…97
97 Body usually fairly fusiform, punctures conspicuous and in rows, east of the Pecos River and always below the southernmost edge of Arizona and New Mexico’s border…E. carbonaria soror
97’ Body only rarely fusiform, punctures variable, west of the Pecos River, or if not then above the southernmost edge of Arizona and New Mexico’s border…98
98 Punctures of elytra simple…100
98’ Punctures of elytra muricate…99
99 Strial punctures and those of intervals subequal in size, often irregularly patterned, generally around northwest New Mexico…E. carbonaria knausii
99’ Strial punctures larger than those of intervals, striae in rows, often in ridges, widespread…E. carbonaria obsoleta
100 Body usually more fusiform, size larger than 17mm, southern Arizona and New Mexico…E. carbonaria chihuahuaensis
100’ Body usually not fusiform, size 17mm or smaller, widespread…E. carbonaria carbonaria