Pollen wasps (Masarinae) are found on all continents but Antarctica, and those of the genus Pseudomasaris occur in western North America in Arizona, California, Oregon, South Dakota, Texas, Utah, and Colorado. Unlike most wasps, which feed other insects to their young, pollen wasps feed pollen and nectar exclusively to their young.

Pollen wasps resemble yellowjackets, except that they have clubbed antennae that are lacking in yellowjackets. Males in the Pseudomasaris genus often have longer antennae than females. Most pollen wasps are black or brown with some yellow, white, or red.