A Revision of the North American Species of Pterocheilus and Notes on Related Genera (Hymenoptera, Vespidae)

Abstract

Some of the largest and most colorful vespoid wasps are contained in the little known genus Pterocheilus. Although North America is well represented in species, which total 31 at the present time as compared to about 66 from other parts of the world, the distribution is almost entirely western and the bulk of the species come from the arid regions of the southwest. This accounts for the many predominantly red and yellow species which fly in company with similarly colored wasps of the large related genus, Odynerus. In Pterocheilus the tendency which occurs frequently in insect genera of having a few relatively common and widespread species, and a large number of rare and localized species is accentuated. The rarity of specimens of the genus in any one collection, and particularly in the eastern states, where most of the work on vespids has been done, has resulted in scattered descriptions only and has left many species undescribed. Furthermore, a logical classification of the genus can be based only on structural characters, which are hardly mentioned in earlier descriptions.