Bethylid Wasps

North American members of this family are tiny or small wasps, rarely over 10 mm long. They are considered to have been derived from a very primitive aculeate stock, and in some features of behavior and development are more like the typical Parasitica rather than the Aculeata. Usually the female stings the host larva a number of times until it is completely and permanently paralyzed. The host larva is left in situ or it may be dragged to a crevice. The bethylid female usually deposits several eggs on each host specimen and the gregarious bethylid larvae develop externally. The Bethylinae and a few Epyrinae prey upon lepidopterous larvae, principally borers and seed-feeders, but also case bearers and leaf rollers. Most of the other bethylids prey upon coleopterous larvae (occasionally pupae), especially species dwelling in the soil, boring in wood or infesting seeds. There have been a few unconfirmed reports of hymenopterous larvae serving as hosts. ~Despite Evans' recent numerous revisions of many of the genera of North American Bethylidae, we must expect that intensive, specialized collecting and biological observations in the future will enlarge our native fauna by as much as 50 percent.

The Bethylidae are a family of aculeate wasps in the superfamily Chrysidoidea. As a family, their biology ranges between parasitoid wasps and hunting wasps.