Ischnomelissa, a new genus of augochlorine bees (halictidae) from Colombia

A new augochlorine bee genus, Ischnomelissa gen. n., is described and figured. The genus is based on a new species from the mountains of Colombia, Ischnomelissa zonata. Ischnomelissa superficially resembles species of Caenaugochlora (Ctenaugochlora), but differs in having a rounded preoccipital ridge, an acute marginal cell apex, an elongated propodeum, and a single gonostylus (not divided into ventral and dor sal gonostylar processes). Color variation within I. zonata and the position of the group in augochlorine phylogeny is briefly discussed. Modified couplets are provided for Eickwort's 1969 key to genera and subgenera in order to correctly identify, the genus.