Poecilanthrax is a large, primarily Nearctic genus of flies belonging to the family Bombyliidae (bee-flies).
Added all species in CAS and BugGuide:
CAS
Poecilanthrax alpha
Poecilanthrax autumnalis
Poecilanthrax californicus
Poecilanthrax colei
Poecilanthrax effrenus
Poecilanthrax eremicus
Poecilanthrax flaviceps
Poecilanthrax litoralis
Poecilanthrax moffitti
Poecilanthrax montonus
Poecilanthrax pilosus
Poecilanthrax poecilogaster
Poecilanthrax robustus
Poecilanthrax sackenii
Poecilanthrax signatipennis
Poecilanthrax tanbarkensis
Poecilanthrax tegminipennis
Poecilanthrax varius
Poecilanthrax willistonii
BugGuide
Poecilanthrax arethusa
Poecilanthrax californicus
Poecilanthrax effrenus
Poecilanthrax eremicus
Poecilanthrax fuliginosus
Poecilanthrax litoralis
Poecilanthrax varius
Combined
Poecilanthrax alpha
Poecilanthrax arethusa
Poecilanthrax autumnalis
Poecilanthrax californicus
Poecilanthrax colei
Poecilanthrax effrenus
Poecilanthrax eremicus
Poecilanthrax flaviceps
Poecilanthrax fuliginosus
Poecilanthrax litoralis
Poecilanthrax moffitti
Poecilanthrax montonus
Poecilanthrax pilosus
Poecilanthrax poecilogaster
Poecilanthrax robustus
Poecilanthrax sackenii
Poecilanthrax signatipennis
Poecilanthrax tanbarkensis
Poecilanthrax tegminipennis
Poecilanthrax varius
Poecilanthrax willistonii
Also added P. brachypus, which seemed to be in neither database, even though the specimen is at CAS: https://monarch.calacademy.org/collections/individual/index.php?occid=2510698&clid=0
Note that a lot of original descriptions are in Cole (1917): https://biodiversitylibrary.org/page/9282035
Pretty good key and photos in Painter & Hall (1960): https://babel.hathitrust.org/cgi/pt?id=coo.31924016936852
Removed P. flaviceps b/c I think it was only included from CAS b/c of specimens ID'd as P. flaviceps fuliginosa (see map and comments in Painter & Hall (1960), which has since been elevated to species, and I think P. flaviceps flaviceps might now be known as P. lowei according to Evenhuis & Greathead (1999).