Subfamily Poemeniinae

Ichneumoninae is the largest ichneumonid subfamily with ~4,300 species in 437 genera. In North America alone, there are around 715 described species, with likely several hundred more awaiting formal description. Ichneumonines are among the most striking ichneumonids due to the striking coloration of many species. The most commonly encountered species are in the sexually dimorphic genera like Ichneumon and Diphyus. Males of these genera are often apparent mimics of stinging wasps (Aculeata) and can be found flying above vegetation frenetically searching for mates. Females tend toward more drab colors like brownish-red and black and are spend more time searching around vegetation for hosts.



All ichneumonines are endoparasitoids of lepidopterans and oviposit into the host larva or pupae and almost always emerge from the host pupa. The only exception is Colpognathus which emerges from the mummified remains of the host final instar larva. Unlike the many ichneumonid groups that oviposit into their concealed hosts with the aid of a long ovipostior, ichneumonine females gain direct access to their hosts prior to oviposition. This often requires digging through soil and leaflitter or crawling under bark crevices and through plant stems. Species in which the females have a rounded or blunted metasomal apex (=amblypygous) always attack larvae and are true koinobionts that oviposit into earlier instar larvae. Those with a sharper metasimal apex with an exposed ovipositor (=oxypygous) may either attack larvae or pupae but probably most commonly oviposit into prepupal larvae or fresh pupae. Ichneumonines are somewhat unusual in that many genera overwinter as adult females in a variety of hibernacula like tufts of grass, beneath bark, and under moss.