The Diapriidae

marginalis considerably longer than both its distance from the basalis and the radial cell; radial cell short (fig. 107); gaster strongly laterally compressed at apex, the apical segments more or less telescoped within segment 3. (antenna extremely slender with the preapical segment about twice as long as wide; pronotal shoulder showing as a sharp tooth but epomia wanting)

marginalis never longer than either its distance from the basalis or the radial cell radial cell relatively longer; gaster never lateral compressed, though it may sometimes be dorsoverntally compressed (Aclista_) and the apical segments may be partly hidden beneath an enlarged third tergite (_Aclista)