I first saw this Reduviid from above (last picture), I thought it was some kind of bee. As it turns out, this species of Assassin bug imitates Meliponine bees. It has a huge expansion of the pronotum, which is probably hollow as in the treehoppers. It is also bee-like in having the abdomen and legs banded. It has two white horns protruding from the head above the insertion of the antennae. It's long thick yellow proboscis is hidden when at rest by closing the front coxae over the top of it. See pictures 6, 7 and 8. One cm in length. Family Reduviidae, Subfamily Harpactorinae.
Found in a forested area, Km 11.5 on the highway between Tuxtla Gutierrez and San Cristobal de Las Casas, Chiapas, Mexico.
"Remarkable examples of mimicry occur between certain groups of Hymenoptera and several taxa of Harpactorini. Species of Notocyrtus are recognized as mimics of meliponine bees, which they resemble mostly because of the angular and inflated pronotum. Two mimetic species pairs have so far been identified: Trigona fulviventris and Ptilotrigona lurida, as models of Notocyrtus dorsalis and N. colombianus, respectively". From Chapter 12: Assassin Bugs (Reduviidae excluding Triatominae by Gil-Santana, Forero & Weirauch in the book: True Bugs (Heteroptera) of the Neotropics (A. Panizzi & J. Grazia Editors).