Abstract
The shape and size of the genital atria of 17 phlebotomine sandflies from Venezuela were examined. The atria were found to express constant characters among individuals of the same species and to be sufficiently different between species to allow taxonomic separation. The spines on the genital armature are described and the characters that can be used to classify individual specimens to species level identified. It is suggested that these characters can be of use on specimens where the spermathecae have been lost or where cryptic species are concerned. Dissection procedures to display the atrium are given.