This work is aimed at the species-level identification of the brachypterous forms of the genus Rhyopsocus found primarily in ground litter throughout southwestern United States, Mexico, and Guatemala. Characters for separation of species used in the present study and in past studies are reviewed critically. A revised definition of Rhyopsocus is given, based in part on venation of macropterous forms. The structure of the complex Rhyopsocus phallosome is compared to that of the species of the genus Psoquilla Hagen. Two new species of Rhyopsocus are described, both from southwestern United States and known to extend into Mexico. The descriptions of Rhyopsocus maculosus García Aldrete, Rhyopsocus micropterus Mockford, Rhyopsocus texanus (Banks) and Rhyopsocus concavus Garca Aldrete are augmented with some new characters. A key to the brachypterous forms of Rhyopsocus species occurring in the area under study is presented. The question of whether the species dealt with here form a clade within Rhyopsocus is briefly discussed but not resolved.