Males are more slender and elongated than females, with significantly longer antennae, but the sexual dimorphism is not as apparent as in many of the Tiphiidae and Thynnidae.

Flowers of the orchid Bipinnula penicillata in subtropical South America resemble females of Pygodasis bistrimaculata, tricking male wasps into attempting to mate and, in the process, provide pollination.

Three additional undescribed specimens from the Ypresian Eocene Okanagan Highlands were referred to the subfamily by S. Bruce Archibald et al. (2018).

[14] In 1847 and 1849 Eduard Eversmann published his "Fauna Hymenopterologica Volgo-Uralensis—exhibiting the species of Hymenoptera which he observed and described in the provinces situated between the Volga river and the Ural mountains."

Two additional species, Campsomeriella annulata (Fabricius, 1793) and Micromeriella marginella (Klug, 1810), were introduced to the United States but failed to become established.