Abstract A new species of Chlerogas Vachal (Halictinae, Augochlorini) is described and figured from Bolivia, correcting a past mis-association of sexes for Chlerogas boliviensis Brooks & Engel. Chlerogas aterrimus sp. n. is described from two males and a single female collected in the Department of Santa Cruz (Provinces of Florida and Caballero) and is distinguished from C. boliviensis, known only from females, and its other congeners. A revised key to the species of Chlerogas is provided along with a new locality record for C. boliviensis.