AbstractNew taxonomic information is given on the identities, generic classification, morphology, relationships, and geographic distribution of several hundred species of proctotrupoid wasps. The paper is based on a study of primary types of 270 species of Scelionidae, many secondary types, and other important material in 40 world museums and private collections with approximately 300,000 specimens of Proctotrupoidea having been examined. Many genera are redefined, and generic diagnoses completed or corrected. The tribal classification is reviewed; four new tribes are proposed in the subfamily Scelioninae, viz. Nixoniini, Sparasionini, Cremastobaeini, and Doddiellini.