Phalotris nigrilatus Ferrarezzi, 1993 is a poorly known species described from a single specimen from Paraguay. Two new specimens make possible a more detailed description of the species, including a description of the hemipenis, and support the validity of the species. Hemipenial morphology provides another character that further supports the inclusion of the species in the nasutus group. We describe variation within the species, probable sexual dimorphism, and the known distribution. It will be necessary to do further work in Paraguay to establish the conservation status of this apparently rare and endemic species.