The following morphological structures of the ovipositor of Homolobus truncator (Say) (Hymenoptera : Braconidae) are described and hypotheses of their functions are proposed: a series of sharp ridges on the distal surface of the notch helps maintain a grip on the inner surface of the host cuticle; the sperone directs eggs away from the inner surface of the ventral valves; a flap-like structure on each ventral valve covers the portal through which eggs pass; the valvillus maintains position of the egg within the ovipositor and acts against the egg to force it out; ctenidia on the inner surface of the ventral valves move eggs along the basal half of the egg canal; recurved barbs at the apex of each ventral valve hook into the inner surface of the host cuticle to maintain purchase while the thick dorsal valve is inserted into the host. The tribe Maxfischeriini (Hymenoptera : Braconidae) is emended to subfamily status based on morphological and biological evidence. A novel egg morphology is described for Maxfischeria, representing a new life history strategy among Braconidae. Based on egg and ovipositor morphology, I suggest that Maxfischeria is a proovigenic, koinobiont ectoparasitoid. Five new species of Maxfischeria are described (M. ameliae sp. nov., M. anic sp. nov. M. briggsi sp. nov., M. folkertsorum sp. nov., and M. ovumancora sp. nov.). A phylogenetic analysis of morphological and molecular characters for the braconid subfamily Euphorinae is presented. The results imply a revised classification that recognizes 9 tribes and 44 genera. Proposed changes include: Meteorus and Zele are recognized as Meteorinae. Planitorus and Mannokeraia are included among Euphorinae and comprise the tribe Planitorini. Cosmophorini, Euphorini, Helorimorphini, Perilitini, Leiophron, and Perilitus are redefined. The following synonyms are proposed: Cryptoxilonini and Dinocampini with Cosmophorini; Myiocephalini and Proclithrophorini with Perilitini; Myiocephalus with Microctonus; Bracteodes, Falcosyntretus, Sculptosyntretus, Syntretellus, Syntretomorpha, and Syntretoriana with Syntretus and are recognized as subgenera; Perilitus (Townesilitus) with Microctonus and are recognized as a subgenus. Transitions in host associations are examined with ancestral state reconstruction. Some ambiguous nodes in the reconstruction are reconciled by examining the overlap in host associations.