The systematic status of the wolf spider genus Sosippus Simon 1888 is reviewed. Males of four species: S. placidus Brady 1972, S. janus Brady 1972, S. michoacanus Brady 1962 and S. agalenoides Banks 1909 are described and fully illustrated for the first time. A cladistic analysis based upon twelve morphological characters resulted in two distinct species-groups within Sosippus. One species-group of the genus occurs from Georgia and Florida in the southeastern United States, westward along the Gulf Coast to south Texas. A second species-group occurs in Arizona and California, and is found in Mexico and Central America as far south as Costa Rica. A new key to the ten species of Sosippus now recognized is presented and updated to include male characters and other features. Collections and observations since earlier studies have provided new information about the social behavior and more widespread distribution of Sosippus janus. Maps have been reconstructed to update the ranges of all species. A preliminary cladistic analysis of the nine species of Sosippus for which both genders are known is presented. Additional critical drawings are provided to illustrate features in the character analysis and facilitate use of the key.