Synonyms and other taxonomic changes
Trophocleptria, which includes the Nearctic Epeolus bifasciatus, was formerly treated as a separate genus (or subgenus)
32 valid spp. in our area, >100 spp. worldwide/total(1)
Absent from Antarctica and Australia, also Madagascar, Oceania, and parts of Southeast Asia, where its hosts (Colletes) are not present.
Most diverse in North America, with 32 spp.
cleptoparasites of Colletes
Differences in the shape of the pygidial plate are used for generic ID of males (shorter and broadly rounded in Epeolus; narrower and with sinuate margins in Triepeolus). This can be difficult to see even in pinned specimens so many males were described in the wrong genus, even by Cockerell and Mitchell! In females the obvious difference is the extent and configuration of a hair patch called the pseudopygidial area (shorter and more transverse in Epeolus). These hairs are often silvery. (J.S. Ascher's comment)
. Onuferko. T. 2018. A revision of the cleptoparasitic bee genus Epeolus
Latreille for Nearctic species, north of Mexico (Hymenoptera, Apidae)