Transverse-wing-folding
Guides
Evaniidae
ensign wasps, nightshade wasps, hatchet wasps, cockroach egg parasitoid wasps
Evaniidae is a family of solitary parasitoid wasps commonly known as ensign wasps, nightshade wasps, or hatchet wasps. The family comprises approximately 20 extant genera containing over 400 described species, with a nearly cosmopolitan distribution excluding polar regions. Evaniidae are immediately distinctive among Hymenoptera due to their unique morphology: the metasoma (abdomen) is attached very high on the propodeum, well above the hind coxae, and is connected by a long, one-segmented, tube-like petiole. The common name "ensign wasp" derives from the characteristic habit of these wasps to jerk their small, flag-like metasoma up and down while walking. All known evaniid larvae are specialized parasitoids that develop inside the egg cases (oothecae) of cockroaches (Blattodea), consuming the host eggs.