Four species are included within the subgenus Diomalopsis Michener & Moure, all of which occur in southeastern Brazil or Paraguay. Undetermined males of this subgenus were collected in the locality of San Ignacio, Misiones. Due to their small size and the brownish coloration of the tegula, they could correspond to the male of E. (Diomalopsis) alexanderi Almeida & Silveira, species described for Paraguay of which the male is still unknown.
References
ALMEIDA, E. A. B. & SILVEIRA, F. A. 1999. Revision of the species of the subgenera of Exomalopsis Spinola, 1853, occurring in South America. I. Diomalopsis Michener & Moure, 1957 (Hymenoptera: Apidae), and a revised key to the genera. Univ. Kansas Nat. Hist. Mus. Spec. Publ. 24: 167-170