The bees are best to be regarded as a specialized subgroup of the superfamily Sphecoidea, and a cladistic analysis results in accepting the "Sphecidae" as being paraphyletic in terms of the bees. The Sphecoidea is distinguished by three strong synapomorphic traits, and it is demonstrated that the bees share at least two apomorphic characters with the "higher" sphecids, leaving the Sphecinae + the Ampulicinae as the least specialized members of the complex. The Sphecoidea is suggested to include the following families, of which the two first constitute the "Sphecidae" of earlier authors, viz. 1) Sphecidae (Sphecinae + Ampulicinae), 2) Larridae (remaining sphecid subfamilies), and 3) Apidae.
Aha-comprising two species endemic to Australia-was previously known from male specimens only. The female A. evensi Menke, 1977 is described here for the first time. The single specimen available originated from very near to the type-locality of the species. The female has the general habitus of Lyroda. -The following autapomorphic traits characterize the genus: 1) Dimorphic claws in both sexes (the outer claw is much enlarged while the inner claw is atrophied); 2) labiomaxillary complex compressed; 3) loss of vol sellar sclerite; 4) loss of aedeagal teeth; 5) pronotal collar with a strong median sulcus; 6) Media of fore wing diverges from M + Cu proximally to cu-a. The possesion of the following characters includes Aha in the Larrini: 1) Second submarginal cell receives both recurrent veins; 2) propodeal synsclerite elongate; 3) posterior propodeal face transversely carinate; 4) lateral ocelli deformed.