Larvae are endoparasitoids of either grasshoppers (Trichopsideinae) or scarab beetles (Hirmoneurinae).

[1] Some are considered important in the control of grasshopper populations.

[1] The family is small but distributed worldwide, with about 300 species in 34 genera.

Nemestrinidae are most diverse in the southern hemisphere, and only six species in three genera occur in the Nearctic region.

[1] Data sources: i = ITIS,[2] c = Catalogue of Life,[3] g = GBIF,[4] b = Bugguide.net[5] Fossils of Nemestrinidae are known from several localities of various ages in Russia, Kazakhstan, Mongolia, Western Europe and North America, with the oldest described fossils being in the Middle-Upper Jurassic Karabastau Formation of Kazakhstan and Daohugou Bed of China.