Mature larvae and pupae of Nomioides patruelis Cockerell and of its cleptoparasite, Chiasmognathus pashupati Engel, collected from the nesting site near Karachi, Pakistan, are described, providing the first account of the immature stages of the respective genera and the first such account for any Nomioidini. An egg of N. patruelis is also described.

An analysis, based on both halictid specimens and descriptions from the literature, reveals that the three subfamilies (Rophitinae, Nomiinae, and Halictinae) of Halictidae can be distinguished on the basis of their mature larvae. A key is provided for their identification. Mature larvae of the tribes of the Halictinae are so similar they cannot be distinguished at present, although studies of additional representatives may yield diagnostic features particularly concerning mandibular anatomy and perhaps body size. Features of the mature larvae when mapped onto a phylogeny of the Halictidae (Pesenko, 2000) provide a hypothesis for the sequence of anatomical changes in the evolution of mature larvae.

Observations during excavation of the nesting site provided detailed, if fragmentary, information concerning nest architecture, provisioning, voltinism, and nest parasites of Nomioides paturelis. These are discussed in relation to information concerning other species of Nomioidini from the literature.

Chiasmognathus pashupati, like its host, is probably multivoltine. The anatomy of the mature larva is similar to that of other Nomadinae, especially that of Ammobatini; however, the pupa is distinct from those of other known Ammobatini. The mature oocyte of the related C. orientanus (Warncke) from Turkey, described previously (Rozen and Özbek, 2003), is likely to resemble that of C. pashupati.