Characteristics of cephalic structures, spiracles, and skins of final-instar larvae of 42 species of 24 genera of the subfamily Ichneumoninae (Hymenoptera: Ichneumonidae) are described and illustrated and keys are given for the separation of tribes, genera, and species. An additional two species that were previously described and illustrated are included in the keys for a total of 44.Larval characteristics support most of the tribal, generic, and specific entities defined on the basis of adult characteristics. They place species of the tribe Phaeogenini as the most primitive and suggest a close relationship between them and species of the tribe Gyrodontini. There is no obvious close relationship between larvae of the tribe Platylabini and other tribes of the subfamily. The tribe Ichneumonini appears to be a relatively distinct group, although the inclusion of the genus Syspasis is questioned. The two subtribes, Trogusina and Callajoppina, of the tribe Trogusini are quite distinct from each other and from other groups of the Ichneumoninae; they appear to possibly have different origins, and perhaps each deserves tribal rank. There is a high degree of taxonomic congruence between the adult and larval classifications.