Pollen wasps, the Masarinae, are unusual wasps that are typically treated as a subfamily of Vespidae, but have in the past sometimes been recognized as a separate family, "Masaridae", which also included the subfamilies Euparagiinae and Gayellinae.

[1] It is a small subfamily, unique among wasps in feeding their larvae exclusively with pollen and nectar, in a fashion quite similar to many solitary bees.

Most species are black or brown, marked with strikingly contrasting patterns of yellow, white, or red (or combinations thereof).

The nests are often constructed of mud, or burrows in the ground, and these can have one to multiple individual cells.

The nests are commonly located in concealed places, such as under rocks or in crevices.