Journal archives for November 2022

November 25, 2022

Griffiths' Treatment of the Genera of Anthomyiidae in the Nearctic Region Part 3: The Pegoplata-Group

Griffiths covered this group in volumes 5-6 of his work, which were published in 1986 and 1987, respecitvely.

1. Genus Pegoplata

Griffiths' notes:
"The genus is the first of a group of genera included by Hennig (1976a: lxiii) in the "Nupedia-group" (here called Pegoplata-group in view of the synonymy of Nupedia with Pegoplata), characterized primarily by the modified structure of the distal section of the aedeagus (expanded, rather uniformly sclerotized without separation of paraphalli from dorsal sclerotization, adorned with pairs of papillae, with acrophallus well developed as separate sclerite in midventral position). The processus longi are retained, and Hennig suggests that the presence of a basal projection on the gonostylus (where it articulates with the processus longus) may be an additional constitutive character of this group...The aedeagal structure validates the core of Hennig's Pegoplata-group containing in his treatment the genera Pegoplata, Nupedia, Myopina, Enneastigma, and Calythea. Another common character of the Pegoplata-group (= Nupedia-group) in this sense is the enlargement of (at least) the female palpi, which probably represents a constitutive synapomorphy although species with enlarged female palpi also occur in a few other genera (such as Paradelia). When apical setulae are present on the scutellum they are very fine, not stouter than the fine ventral setulae...the apical setulae are also very fine in Myopina and Calythea.
...I amalgamate Pegoplata and Nupedia (= Pegomyia virginea and P. dissecta groups of Huckett 1941), since I can find no consitutive modifications (autapomorphies) characteristic of Nupedia alone...
Unlike in Myopina, strong sexual dimorphism in eye size and frons width is normally retained in Pegoplata; only in P. abnormis (Stein) is a male form with rather widely separated eyes brown. The interfrontal setae are normally well-developed in both sexes, tending to be displaced forwards rather than reduced in males with closely approximated eyes.
The prosternum and the hypopleuron are bare, and the notopleural depression normally lacks setulae additional to the usual two long setae in all species of Pegoplata; the scutellum is finely pubescent apically and ventrally, bearing the usual two long marginal pairs of setae and a shorter discal pair. The hind tibiae lack an apical pv seta. The pulvilli are sexually dimorphic, enlarged to a varying degree in males but always small (less than half as long as the 5th tarsal article) in females.

...The male 5th sternite is flat and more or less heart-shaped (with convex outer margins), with dense inner fields of short setulae or spinules...
...The only species of Pegoplata whose life-history has been studied in detail is P. aestiva (Meigen), whose larvae feed in faeces. Information for other species is sketchy or in need of confirmation...
...In the Nearctic Region species of Pegoplata can be found in a wide range of habitats from hot desert to the alpine and low arctic zones."

Characterization tables:
Griffiths did not recognize subgenera for Pegoplata, despite containing the former genus Nupedia, because he believed the subdivisions of the genus required more study. One characterization is provided. Four sections were recognized: the P. palposa section, P. infirma section, P. acutipennis section, and the P. cuticornis section, with the Palearctic P. debilis superspecies as incertae sedis. The photographic characters used are the length of the mentum, development of a keel between the antennae on the face, projection of the lower facial margin, number of rows of the postocular setulae of males, pubescence of the arista, and ventral costal chaetotaxy. Only the P. (section infirma) aestiva superspecies has the mentum elongated and a swollen keel on the face between the antennae. In other species, the mentum is short and the facial keel is absent or narrow. Most species have a lower facial not projecting beyond the level of the parafrontal angle except for the P. aestiva superspecies and P. (section cuticornis) nasuta with an ambiguous state for species P. cuticornis. The number of rows of dorsal postocular setulae on the male is varied across the genus. They are present in 2-3 rows in the P. aestiva superspecies, P. infirma, P. (section infirma) tundrica, P. nasuta, and an ambiguous state for P. cuticornis. The P. palposa superspecies and P. (section palposa) pictipes have a plumose arista, whilst other species have an arista with only short pubescence. The species in the P. palposa section have the lower surface of the costa extensively setulose, with ambiguous states for the P. (section acutipennis) acutipennis superspecies, P. (section acutipennis) abnormis superspecies, and P. valentinae.

My comments:
This poorly known genus has about 10 species occurring in our area. Fortunately, the genus can be somewhat recognizable if certain features are paid attention to. The third antennal segment is 1.4-2.5 times as long as wide. The prementum is finely dusted to shining, and the palpi of at least the female are enlarged apically. Palpi can be difficult to see and judge in photos, but Griffiths has referred to palps expanding distally as expanding to "two thirds the width of third antennal article" for a species of Myopina. Scutellum with ventral hairs present. Proepisternum with or without setulae. Thorax with 3(-4?) postsutural dorsocentral setae. Anterior post-sutural supra-alar or prealar seta in most species short or absent. Presutural acrostichal setae usually in widely separated rows. Griffiths did not provide information about the anepisternum for this genus, but P. palposa may lack an anterodorsal seta here. Chaetotaxy of the anepisternum was not considered in descriptions until next one or two volumes, although alas it is probably one of the most distinguishing and photographable characters in the family. Scutellum mostly bare dorsally to largely setulose. Mid tibia usually without av exclusive of apical setae. Hind tibia usually with 2 pd, the apical pd seta conspicuously longer than the other, without any pv setae in both sexes.
The Manual of Nearctic Diptera does not treat this genus well. Pegoplata aestiva was outdatedly placed under the genus Paregle in couplet 13. Some sources have suggested Pegoplata aestiva may have four post-sutural dorsocentral setae, but I have not been able to remember which. Longest aristal hairs may at most be as long as the antennae are wide (in P. palposa superspecies and P. pictipes). The mid tibia of only P. aestiva may have a mid av seta, keying it to couplet 34's "Adia". Going to couplet 35 for species without the av and 2 pd (or less) on the hind tibiae, the species of Pegoplata with a setulose ventral costal surface are difficult to place, as these species will have interfrontal setae present, although perhaps short in the males. Separating Pegoplata from Pegomya can be tricky and may require species by species separation, looking at acrostichal arrangement, numbers of posthumeral setae, color, and presence of interfrontal setae where useful. Otherwise, remaining species will key to Nupedia with the prementum being "pruinose". This is mostly true with most species having a "finely dusted" prementum instead of entirely shining per Griffiths, however, P. infirma and P. tundrica are two exceptions of "Nupedia" with a rather shining to shining prementum. Furthermore, Pegoplata juvenilis can have up to 4 posterodorsal setae on the hind tibiae in the female. This keys it all the way to Paraprosalpia (=Alliopsis) in couplet 67, where the apical setulae, if present, are weak, but differs by the finely dusted and not polished prementum, the long aristal pubescence, and probably a few other characters, such as lack of setulae behind the vibrissal prominence (like for Pegomya vs Eutrichota). Alliopsis is a difficult to define genus but made up of distinctive groups of species that are usually easily eliminated from options when compared to species of Pegoplata.

2. Genus Myopina

Griffiths' Notes:
"This small Holarctic genus was placed in the Pegoplata-group by Hennig (1976a) on account of the presence of papillae on the distal section of the aedeagus and the nature of the articulation between the gonostylus and the processus longus. This opinion is accepted here, although the male genitalia are so extraordinarily modified...that it will be difficult to have confidence in the placement of the genus unless species with less modified structure are discovered. The earlier concepts of Fucelliinae or Myopinini, in which Myopina was included by earlier authors...were unnatural mixtures, as Hennig says.
The previously described valid species belonging in Myopina are three only: M. myopina (Fallen), M. scoparia (Zetterstedt), and M. crassipalpis Ringdahl. I here add one new species , M. martini n. sp...
Species of Myopina will be recognized by the following combination of characters: The head structure (Fig. 834) is not sexually dimorphic, with the relatively small oval eyes equally widely separated in both species; crossed interfrontal setae are always present; additional post-ocular setulae are present dorsally below the marginal row; the third article of the arista is thickened on its basal third to half; the palpi are somewhat expanded distally at least in females.
The male abdomen is swollen (more or less circular in cross-section)...
...The thoracic chaetotaxy is in no way unusual in Myopina, and in particular the fine ventral setulae of the scutellum are present as in most other Anthomyiidae. Huckett's (1965a, 1971a) characterization of "Myopinini" with the phrase "scutellum usually without hairs on ventral surface" did not apply to Myopina. The propleural depression and hypopleuron are bare, and the notopleural depression lacks setulae additional to the usual two long setae in all species. The scutellum bears the usual two long marginal pairs of setae and a shorter discal pair; its apical setulae, when present, are short and fine (not stouter than ventral setulae). The lower squama is weakly expanded or linear. The hind tibiae lack an apical pv seta. The legs are strongly sexually dimorphic, displaying unusual modifications (varying according to species) in the males.

Species of Myopina are not commonly collected and their immature stages are unknown...unique synapomorphies of the males of [M. scoparia and M. crassipalpis] are the presence of a complex ventral sclerite between synsternite (6+7) and the hypandrium...and the presence of a tuft or brush of setae on the posterior surface of f3."

Characterization tables:
None.

My comments:
This small genus of distinctive flies are so unusual for the family that they would probably be identified no further than Calyptratae or even mistaken as an oestroid family if wing venation is ignored. Nonetheless, very few identified representatives are known, but images of some Myopina myopina can be found readily online. In addition to Griffiths' characterization, these flies also have very wide gena, the prementum finely dusted to shining, scutellum broadly bare centrally, crossvein dm-cu usually straight, at most slighty bent, ventral surface of the costa usually bare, at most with submarginal row of fine setulae, and legs dark. The prosternum in only M. martini is setulose. Two of the four species, M. myopina and M. scoparia, have the scape and pedicel yellowish. Males of 3 species are known, excepting M. martini. They exhibit much sexual dimorphism in the legs, with M. myopina males having a bowed first hind tarsomere, and other species differing from females by at least a slightly swollen hind femur and at least the hind tarsi shortened. The male of M. martini is unknown but would be the missing key to understanding the relationships of these species to each other.

3. Genus Calythea

Griffiths' notes:
" The above synonymy follows Ackland (1968) and Hennig (1968), and has been adequately discussed in Ackland's paper. In North American literature, only the names of Calythea and Anthomyiella have been used...It is possible that Enneastigma (Stein, 1916: 122), containing three species from southern Europe, can also be included in Calythea...
...In comparison with Pegoplata and Myopina, Calythea (and Enneastigma) stand out as apomorphous (derived) with respect to the reduced vestiture of the gonostylus...
...Calythea is more diverse in the Old World than the New (represented in the Afrotropical and Oriental, as well as Palearctic, regions). Only five species occur in the Nearctic region. Four of these are evidently very closely related (showing the same characteristic setulosity of the hypopleuron and identical genitalia), belonging to what I propose to call the C. micropteryx superspecies. Since the Neotropical C. comis (Stein) also belongs to this superspecies, we are probably dealing with the results of a Tertiary invasion of the New World. The most northern member of this superspecies, C. bidentata (Malloch), retains a Holarctic distribution. The fifth Nearctic species (not belonging to the C. micropteryx superspecies) is the holarctic C. pratincola (Panzer)...
...The Nearctic species of Calythea are all small flies (less than 5 mm wing length), easily confused with small muscids or fanniids on superficial inspection on account of the enlarged lower squama (larger in area than upper) and distally faint anal vein. They can be readily recognized (in both sexes) by their possession of bright silvery grey-dusting on the abdomen , forming a contrasting pattern with opaque sooty areas (Fig. 862). As in other members of the Pegoplata-group, interfrontal setulae are retained in all females and most males (with the exception of C. pratincola), the female palpi are (at least slightly) expanded and the scutellum retains ventral setulae (with apical setulae, when present, very fine, not stouter than the ventral setulae). The normal sexual dimorphism in eye size and frons width is retained. The thoracic chaetotaxy varies between species, providing many diagnostic characters; among the sclerites described in this work only the propleural depression is bare in all species (hence omitted from the species descriptions); the scutellum bears the usual two long marginal pairs of setae and a shorter discal pair. The hind tibiae lack an apical pv seta. The pulvilli are only weakly dimorphic (not much longer in males than in females)...
...The larvae of two species of Calythea, C. micropteryx (Thomson), and the Palearctic C. nigricans (Robineau-Desvoidy), are known to feed in mammalian feces."

Characterization tables:
None.

My comments:
These small flies belong to a complex of various calyptrate flies across families that show sometimes contrasting patterns of black and silvery white dusting that can be very easily confused for each other. Species in Limnophora, Gymnodia/Brontaea, Anthomyia, some tachinids, and probably some more I am forgetting. It is important to keep in mind wing venation, leg chaetotaxy, presence or absence of interfrontal setae, maybe the elongated basiventral seta on the base of the hind first tarsomere, maybe some color details, and maybe dorsocentral setae when trying to determine these genera from each other. The anal vein won't be of much help as this genus has it rather faint distally. There are only 4 species known north of Mexico with one additional species from Mexico included in Griffiths' treatment. They are relatively homogenous in structure except for color, variations, and minor chaetotaxy, so it can be described further here.
Prementum finely pruinose, thorax mainly black with silvery areas in the males, but varying from densely dusted with black patches in C. pratincola to almost entirely dark in C. crenata, more dusted in females and with coppery sheen, abdomen with dark and light areas, more densely dusted in females, legs dark, wings slightly yellowish tinged to brownish tinged.
Male eyes narrowly separated, no wider than width of anterior ocellus, eyes pilose only in the Mexican species C. crenata, gena below lowest point of eye nearly eliminated (extremely narrow) except for 0.1-0.15 times eye height in C. pratincola, peristomal/lower facial margin scarcely to strongly projecting anteriorly beyong parafrontal angle, face with (C. monticola) or without a shining ocellar tubercle separating antennal bases, with or without a keel betwen antennae, various in width and height, interfrontal setulae short or absent in males of C. pratincola only, well-developed in other forms, genal setae in 1-2 rows, not described to have setulae behind the vibrissal prominence, postocular setulae usually in 1 row dorsally, only known in the female of C. pratincola to be in 2 rows, third antennal article 1.6-1.8 times as long as wide, arista with short to very short pubescence, palpi not expanded to distinctly expanded distally to about width of third antennal article, wider in females, mentum 0.3-0.6 times as long as head height.
3 pairs of presutural acrostichals usually in widely separated rows at least anteriorly, rather narrowly in some C. bidentata, with or without additional setulae in between, 1 anterior and 2 strong posterior posthumeral setae, notopleuron with setulae anteriorly or bare, prealar short or absent, scutellum bare dorsally, largely bare in C. pratincola, katepisternal setae largely arranged 1+2, with anterior seta potentially short or reduced in the female of C. pratincola, prosternum and hypopleuron setulose (at least laterally and anteriorly, respectively) in all species except C. pratincola.
Costal spinules of wing all shorter than costal width, lower surface of the costa bare. Crossvein dm-cu almost straight.
Mid femora without distal anterior or anteroventral setae. Fore tibia with 0-1 ad (if present, long), 0-1 p; mid tibia with 0-1 ad, 0-1 pd, 0-2 p; hind tibia with 1-2 av, 1-2 ad, 1-2 pd, the latter very long if only one present.

References:
Evenhuis, N.L. & Pape, T. (editors). 2022. Systema Dipterorum, Version 3.9. http://diptera.org/, accessed on 4 August 2022.
Gomes, L.R.P., Souza, D.S., Carvalho, C.J.B. de. 2021. First insights into the evolution of neotropical anthomyiid flies (Diptera: Anthomyiidae). Systematics and Biodiversity 19(7): 724-737.
Griffiths, G.C.D. 1983-2004. Anthomyiidae. Flies Nearctic Region 8(2): 1-160 (=no. 1), 1983; 161-288 (=no. 2), 1983; 289-408 (=no. 3), 1984; 409-600, (=no. 4), 1984; 601-728 (=no. 5), 1986; 729-952 (=no. 6), 1987; 953-1048 (=no. 7), 1991; 1049-1240 (=no. 8), 1991; 1241-1416 (=no. 9), 1992; 1417-1632 (=no. 10), 1993; 1633-1872 (=no. 11), 1996; 1873-2120 (=no. 12), 1998; 2121-2288 (=no. 13), 2001: 2289-2484 (=no. 14), 2003: 2485-2635 (=no. 15), 2004.
Holmberg, R.G. 2017. Entomological Society of Canada/La Société d’entomologie du Canada, https://esc-sec.ca/wp/wp-content/uploads/2017/02/Obit_Griffiths_Graham.pdf
Michelsen, V. 2000. Oldest authentic record of a fossil calyptrate fly (Diptera): a species of Anthomyiidae from early Coenozoic Baltic amber. Studia Dipterologica 7: 11–18.
Michelsen, V. 2010. ANTHOMYIIDAE (ANTHOMYIID FLIES). In: Brown, B.V., Borkent, A., Cumming, J.M., Wood, D.M., Woodley, N.E. & Zumbado, M.A. (Eds.), Manual of Central American Diptera. Vol. 2. NRC Research Press, Ottawa, pp. 1271-1276.

Posted on November 25, 2022 06:41 AM by aispinsects aispinsects | 0 comments | Leave a comment

November 27, 2022

Griffiths' Treatment of the Genera of Anthomyiidae in the Nearctic Region Part 4: The Alliopsis-Group

Griffiths work from 1987 and 1991 volumes 6 and 7

  1. Genus Paradelia
    The first draft of this section was entirely deleted by accident so this will be a minimal treatment.

Griffiths' Notes:
"Hennig (1976a) also characterizes the Alliopsis-group by the structure of the proboscis (shining mentum, msall labella , strong prestomal teeth); indicative of predatory habits. This seems to be correct since sclerotized prestomal teeth can often bee seen in preserved specimens of all speces. Iwata (1983) has reported the presence of strongly sclerotized teeth in Anthomyiidae only in Alliopsis (as Paraprosalpia) and Pegoplata, but since he examined only seven selected species of thr family (further information on the distribution of tis character is needed. Predatory habiys have so bfsfr been only confirmed forn the genuys Alliopsis,. The mentum is shining in all species, a fact helpful when sorting collections (since anything with dusted mentum can be immediately ruled out from possibly belonging to tje Alliopsis-group).
...In the present treatment, I follow Michelson's (1985) subdivision into two genera, Alliopsis s.l. (including Paraprosalpia) and Paradelia s.l. (including Pseudonupedia)...
...All species of Paradelia retain the sexual dimorphism normal in Anthomyiidae (narrow-fronted males with reduced frontal chaetotaxy and with enlarged pulvilli, broad-fronted females with ors and ori differentiated and with small pulvilli). Females with narrow frons and other masculine secondary sexual characters and males with feminine secondary sexual characters (broad frons etc), both of which are found in Alliopsis, do not occur in Paradelia.
Other common characters omitted from the descriptions of Paradelia pspecies below are follows: eyes without evident pubescence; face flat to slightly convex centrally, without prominent keel, not constricted ventrally (vibrissae separated by more than shortest distance from each to eye margin); arista not angled; vibrissal prominence without additional setulae behind vibrissa; notopleural depression without setulae additional to the usual two long setae; scutellum finely pubescent ventrally; bearing the usual two long marginal pairs of setae and a shorter discal pair; propleural depression bare; hypopleuron bare; hind tibiae without apical pv seta; tarsi without unusual modifications or adornment...

...Species of Paradelia were erroneously includd in Pegomya in Huckett's (1941) work (partly heterogenous "intersecta-subgroup of the flavipes group" partly as species not included in any group). Theyb have been generally cited under the genus Pegomya in Nearctic literature, except for the introduction of Pseudonupedia for some of the species in Huckett's ladt works during the 'seventies."

Characterization tables:
There is one. There is 15 species in the genus in our area. Most characters only genitalic. Divided into subgenera Pegomyiella with only P. lunatifrons in it and Paradelia, latter divided into P. lundbeckii section and P. intersecta section, which is divided into species solae and P. intersecta subsection, which is divided into species solae and P. intersecta superspecies. P. lunatifrons is the only species of Anthomyiidae besides those in the genus Egle that has the costal more swollen at the junction with vein R1. The only photographic characters are develooment of setae on third sternite in males and the expansion of female palpi. Only P. lundbeckii section has the males with the third sternite with outstandingly long setae and 4th sternite much enlarged as well. Female palpal expansion is quite variable among the genus, with females not known for some species.

My comments:
This genus may be difficult to recognize from Pegomya. Species with pale-colored and dark-colored legs exist. As stated, the prementum is shining.
Males have eyes narrowly separated, not wider than diameter of anterior ocellus, parafrontals not exceeding third antennal article in width, peristomal/lower facial margin not projecting beyond level of parafrontal angle, gena narrow, 0.1-0.2 times as high as eye height, genal setae in 1 row unless otherwise stated, cruciate interfrontal setae various in male, present in female, third antennal article usually 2 times as long as wide or longer, arista with at most short pubescence, palpi of many females enlarged, vibrissal prominence without additional setulae behind vibrissa.
Scutellum always with hairs on ventral surface, prosternum bare or setulose, middle of proepisternum without setulae, katepimeron without hairs, thorax with 3 ps dc, apical setulae of scutellum may be distinctly stronger than ventral hairs, multiple posterior posthumeral setae often present (1+2 or 1+3), notopleura without additional setulae, prealar seta shorter than posterior notopleural seta, scutellum largely bare centrally, anepisternum potentially without anterodorsal setula, but this remains unreported in Griffiths.
Tibial chaetotaxy similar between males and females. Hind tibia usually with 2 pd setae, almost never with any pv setae, mid or apical (1 posterior seta may be present in P. palpata). Mid tibia without an av, exclusive of apical setae.
Costa of wings without widely spaced coarse setae on lower surface distal to subcostal break, this lower surface also ranging from bare to densely setulose, lower calypter not distinctly extended beyond upper one, costal spinules all short, including pair before subcostal break, vein A1+CuA2 traceable to wing margin.
The key in the Manual of Nearctic Diptera does not include the genus Paradelia. It includes the group of species making up the former Pseudonupedia and the remaining species as Pegomya. Most of the species are only known to have 2 posterdorsal setae on the hind tibiae. They will key readily to couplet 35. A couple species have the ventral surface of the costa with numerous setulae, but most of them have cruciate interfrontal setae present. Regardless they probably key to Pegomya/Eutrichota on that couplet. The other species will then key to couplet 37, but which is problematic because several species have medial setae on the fore tibiae. The apical scutellar setulae were not described anywhere by Griffiths for this genus, but the male fifth sternite is perhaps more setose in "Paraprosalpia". The species then might loosely keyed to Pseudonupedia. The species P. setiventris, P. ventribarbata, P. palpata, P. trigonaloides can have 1 or 3 posterodorsal setae on the hind tibiae, thus keying to couplet 38, where the sexes are divided into males going to couplet 39 and females to couplet 56. The lack of an apical pv seta (In both sexes) brings it to couplet 40, the presence of male cruciate interfrontal setae to couplet 41, and the setose processes of sternite 5 key it to couplet 42. Most of the species that key there will key to Pegomya on account of the yellowish legs, but with the exception of P. trigonaloides, which have all dark legs. This species is difficult to key further because the posterior series of setae on the anepisternum is not described in Griffiths' work here, and leaves it at odds with Hydrophoria. The species may be separated from Hydrophia by the arista with at most short pubescence or the short prealar. It will otherwise key to couplet 55, in which P. trigonaloides keys closest to the genus Delia. The species probably does not have outstanding setula below anterior notopleural seta on the anepisternum, has 1 pd on the mid tibiae, is known only from Yukon Territory, and does not have medial pv setae on the hind tibiae in males. Griffiths did not describe the epandrium or syntergosternite 7+8 of P. trigonaloides. Unfortunately for females, the species of Paradelia without 2 posterodorsal setae on the hind tibiae key dubiously. Paraprosalpia is met at couplet 67, where the status of the scutellar setulae is not known, prementum is polished, and status of segment 5 of the abdomen as relatively short or not is not known. Cruciate interfrontal setae are present and this combined with lacking discal setae on tergite 5, anterior katepisternal setae no more than 1, and mid tibiae with 1 posterodorsal seta key it to couplet 75, where they will all most likely key to genus Delia, but otherwise to any of the other genera Lasiomma and Pegomya based only on tibial colors.

2. Genus Alliopsis

Griffiths' notes:
"...Michelsen (in correspondence) reports that the possession of specialized raptorial modifications of the prestomal teeth is also a constitutive character of Alliopsis. Details of the tooth structure are not considered in my descriptions, since I have not made preparations of the mouthparts. Good illustrations of the mouthparts (including prestomal teeth) in A. silvestris (Fallen) have been published by Sychevskaya (1981).
There is considerable diversity among species of Alliopsis with respect to the develpment of the male 5th sternite processes and secondary sexual characters. The genus includes groups with normal sexual dimorphism in head structure, pulvillar development etc, groups whose females have acquired male secondary sexual characters, and groups whose males have acquired female characters. As a result of this diversity many generic or subgeneric names have been proposed. Hennig (1966a-1976a) synonymized most proposed names under Paraprosalpia, retaining Alliopsis sensu stricto as a separate small genus. But Paraprosalpia in his sense cannot be characterized as a monophyletic group. More probably it is paraphyletic through exclusion of Alliopsis s. s. For this reason I follow Michelson's (1985) proposal of expanding the concept of Alliopsis (the earliest name available) to include Paraprosalpia. I recognize Alliopsis in Hennig's sense as the A. glacialis section. Pseudochirosia, recognized by Hennig as a subgenus of Paraprosalpia, merits no higher rank than superspecies, having hypopygial structure typical of the A. conifrons section. In Huckett's works and other previous Nearctic literature the generic names Alliopsis and Paraprosalpia were used in the same senses as in Hennig's work, except that Pseudochirosia was misplaced in the heterogenous "Myopinini" on account of the broad-fronted males. The monobasic Circia was misplaced in the "Fucelliinae" for the same reason...
In contrast with the colour variation shown in the sister-group Paradelia, there is little color variation in Alliopsis. All Nearctic species except A. tinctipennis have entirely dark body and appendages in both sexes...
Since the primary subdivision of this genus is unclear, I do not recognize subgenera in the present treatment. The recognition of a multitude of subgenera, as proposed by Ringdahl (1942), has not been supported by other authors. I have arranged the species in three sections: the A. glacialis section, A. silvestris section, and A. conifrons section. There remain 15 Nearctic species (partly included in superspecies) not included in these sections...
...The genus Alliopsis is confined to the Palearctic and Nearctic regions, with greatest diversity in the mountains and in the boreal to subarctic zones. Many species have holarctic distributions. None have been found south of the Mexican border.
Common characters omitted from the descriptions of Alliopsis species below are as follows: Mesonotum with 2 (presutural) + 3 (postsutural) pairs of dorsocentral setae (except in A. tinctipennis); notopleural depression without setulae additional to the usual two long setae; scutellum finely pubescent ventrally, except in A. tinctipennis, bearing the usual two long marginal pairs of setae and normally a shorter discal pair (except in A. benanderi and A. tinctipennis); propleural depression bare; hypopleuron normally bare (except in A. brevior); hind tibiae without apical pv seta..."

Characterization tables:
One massive table present with numerous photographic characters. As Griffiths said above, the species were divided into three sections with no subgenera. There are also no subsections, infrasections, etc except for superspecies. The variation of the genus is so large that I don't think they should be in the scope of this synopsis.

My comments:
This genus can be difficult to characterize as one genus than as a whole with distinctiveness manifesting in the parts making it up. The predatory habit of muscoids typically comes with a Coenosia-like repertoire that can actually be recognized in the field. They may stand somewhat conspicuously on foliage waiting for prey instead of squatting more like most flies. Most Alliopsis species can be recognized as either being quite extensively hairy and having strong setation, even on the eyes, or have relatively narrow frons in both sexes along with conspicuously long tibial setae (like coenosiine flies; the A. silvestris section), or a distinct species with 4 postsutural dorsocentrals, yellow legs, and maculate wings (A. tinctipennis), a species with long antennae, an arista distinctly bent, and sometimes with opaque whitish wings (A. fractiseta superspecies), or species with some setulae situated behind vibrissa. Apparently only about 2 species don't fit in any of those groups in our area (A. laminata and A. benanderi, both from Alaska to Yukon Territory) but some species with setulae behind the vibrissa may have them few.
Male eyes variously separated, proboscis not long, slender, or tubular, eyes densely pilose to bare, prementum not conspicuously enlarged in either sex, longest aristal hairs not longer than width of first flagellomere, cruciate interfrontal setae usually present in both sexes (except some species in the A. glacialis section), head at maximum length shorter than high, vibrissa in nearly all species with at least a few setulae behind on vibrissal prominence (except some A. silvestris superspecies, A. laminata, and A. benanderi), face often with a convex or bulging area.
Katepisternal setae typically 1+1(2) to 1+3, thorax with 3-4 postsutural dorsocentral setae (only 4 in A. tinctipennis), prealar shorter to longer than length of posterior notopleural seta, discal setae of scutellum short or absent (A. benanderi and A. tinctipennis), katepimeron almost always bare, only with a few setulae in some A. brevior.
Mid tibia with or without a/av. Hind tibia with or without pv setae, with 2-7 pd, often 2.
Costa with (A. tinctipennis) or without widely spaced coarse setae on lower surface distal to subcostal break, this surface bare to almost entirely setulose, lower calypter not distinctly extended beyond upper one, vein A1+CuA2 traceable to wing margin.
Abdomen in male conical.
In the Manual of Nearctic Diptera, the genus Circia containing only the distinctive species C. tinctipennis is now a synonym of Alliopsis. It does indeed key to couplet 4, with the ventral surface of the scutellum without hairs (much like the dorsal surface), widely spaced coarse setae distal to subcostal break on the ventral costal surface, and a single pair of presutural dorsocentral setae. No changes in its range from Alaska to Alberta are noted. Alternatively, one could recognize it by its very distinctive pale whitish body, with maculate wings, yellow legs, and nearly arctic distribution. Griffiths was satisfied with placing the species into Alliopsis sensu lato vs in "Fucelliinae" based on the hypopygial structure, in contrast to Huckett's treatment in the Manual which was derived from Malloch (1929). Its position within Alliopsis though, is unsettled. Nothing is known of the life history for this unusual species, but Griffiths posits the small eyes and long costal spines may suggest a behavior like Eutrichota, occupying the subterranean burrows of animals. Griffiths found no additional material since Malloch in 1929. Further in the key, A. brevior of the A. glacialis section may rarely key to couplet 15 if the katepimeron has hairs, to which the bare prosternum and lack of tridentate abdominal pattern will key it to Hydrophoria, from which it can be separated by the pilose eyes, being in Alliopsis s. s., the almost bare arista, the short third antennal article, in most cases by only one strong anterior katepisternal setae, and likely by color or other characters. Otherwise, the remaining Alliopsis glacialis section will key to Alliopsis s. s. in couplet 27 with the eyes "more or less densely haired". This is true for most species, but also very close to true for the rest, A. brevior and A. incompta, that have them rather sparsely clothed with short, fine pubescence, as opposed to bare or with at most extremely sparse hairs only visible under high magnification in other Anthomyiidae. It gets difficult further in. Many species have 2 pd on the hind tibiae, but a few have none to 1, the same ones may have 0-3, posteroventral setae may or may not be present (there is no sexual dimorphism with respect to this character in this genus), and females may or may not have narrowed frons. The A. glacialis section have at least 3 pd setae, the female frons is narrowed, and pv/p setae are present. In the A. silvestris section, only two species can have 2 pd on the hind tibiae, A. pseudosilvestris and A. angustitarsis, both of which have 1 (outstandingly long) pv seta on the hind tibia (in both sexes) and a narrowed female frons. The A. conifrons section has A. fractiseta, A. albipennis, A. badia, and A. laminata known to potentially have 2 pd setae, but all members of the section have no pv setae on the hind tibiae as well and the females don't have narrowed frons. Of the remaining species not in sections, the species A. pilitarsis, A. benanderi, A. uniseta, A. littoralis, A. aldrichi, and A. brunneigena can potentially have 2 pd setae in some form or another. However, they all do not have pv setae and the female eyes are widely separated. Thus, the logic of this key's couplet is relatively without fault...either there are 2 posterodorsal setae and of these the female frons width is narrowed or not, and pv setae are present or not, or there are none, 1, or at least 3 posterodorsal setae. The A. glacialis section, if not keying prior, has the luxury of having both adorned hind tibiae, pv setae, and narrowed frons in the females. This section, the A. silvestris section, and the specimens without 2 pd key to couplet 38, and the species of the A. conifrons section and those that are solae with 2 pd setae key to couplet 33. Going to couplet 33, some of the species have an anteroventral seta on the mid tibia, exclusive of the apical seta, so would key to Pegomya in couplet 34, from which they can be separated by distinctive characters (A. albipennis), setulae present behind vibrissa, or an absent prealar seta. Going to couplet 35, the species that key here have the lower costal surface at least largely bare, keying to couplet 37 with the shining prementum, and then all of those species keying to Paraprosalpia with distinct fore tibial medial setae EXCEPT sometimes A. uniseta, pilitarsis, and benanderi...which can be separated from "Pseudonupedia" well from this single journal page since that is a synonym of Paradelia (setulae on vibrissa (A. uniseta, A. pilitarsis), or prealar absent (A. uniseta, A. benanderi), long setulae on hind tarsi (pilitarsis), or nearly lacking discal scutellar setae (A. benanderi)). Griffiths does not make any mention of the apical scutellar setulae in Alliopsis. The one specimen of A. pseudosilvestris I can see on Canacoll's digital collection of specimens has apical setulae that appear strong but I can't be sure. No mentions are made on the apical setulae on the scutellum of Paradelia or the P. intersecta section (formerly Pseudonupedia) as well. We next have the species on the path of couplet 38 which separates the sexes, leading to 39 and 56. Couplet 39 asks for the presence of pv setae on the hind tibiae and makes an exception when it is absent, "but with a single posterior bristle near middle in some Paraprosalpia". This is correct except for some A. silvestris which can apparently have 2, but also 1. Otherwise, the A. silvestris section will key to Paraprosalpia in couplet 41. Should there be a male A. silvestris with 2 posterior setae, the realm of genitalia has been entered, thus note that hind tibia is without apical pv, sternite 6 is bare, abdominal sternite 5 is not lengthy and notched on the inner border (scutellum with distinct ventral hairs), syntergosternite 7+8/the pregenital sclerite is strongly shining, and the abdomen is conical, keying to couplet 49 where it will butt heads with Lasiomma (as both Acrostilpna and Lasiomma in the key), but differing from that genus by the outstanding tibial setae. The A. glacialis section should not make it this far with its distinctive characters at this point, but it should key similarly. If not, it may be because the pregenital sclerite is is not shining, and it would key to Pegohylemyia (=Botanophila) and Delia which they differ by having at least 3 pd setae on the mid tibiae. The females of the same A. glacialis section, A. silvestris section, and other specimens without 2 pd key to couplet 56, which can then be easily keyed to couplet 67.. The shining prementum will then place it around Paraprosalpia, with again the apical setulae of the scutellum to be discussed. Tarsomere 5 is not greatly expanded in the species of Alliopsis; only at most tarsomeres 2 and 3 in the females of the A. silvestris section.

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