1. Genus Krombeinella Pate, 1947

Type species: Hylaeus thoracicus Fabricius, 1793, ♂, by original designation.

Eighteen species of this genus occur in the Palaearctic Region, mainly in the Mediterranean (Pagliano et al. 2020) and one species in Oriental Region (Williams et al. 2019). Only one species of this genus has been reported from Azerbaijan.