Life History Studies of Pepsis and Hemipepsis Wasps in California (Hymenoptera, Pompilidae)

Wasps of the genera Pepsis and Hemipepsis are our largest hymenoptera. A large Pepsis is about an inch and a half long; the tarantulas, their common prey and provision for the young of these wasps, are our largest spiders. Encounters between “tarantula hawks”, as these big wasps are frequently called, and tarantulas have often been observed and occasionally recorded in literature. But there has not been much information on what species of wasp attacks what species of tarantula, nor on some of the aboveground operations subsequent to these encounters. This paper supplies some of these data, and partly fills in the almost complete void hitherto existing on the early stages of these pepsine wasps, as well as the operations of the mother wasp in the dark underground where she prepares the way for her offspring that she will never see.