Taxonomy of the wide-ranging Nearctic velvet ant genus Dilophotopsis Schuster (Hymenoptera: Mutillidae) is reviewed using molecular and morphological comparisons. The validity of the four designated subspecies of Dilophotopsis concolor (Cresson) is examined. Dilophotopsis concolor paron (Cameron) is morphologically and molecularly distinct from the other three subspecies, and it is raised to the species level [D. paron (Cameron), nov. stat.]. Dilophotopsis concolor crassa (Viereck) and Dilophotopsis concolor laredo Schuster are morphologically indistinguishable from the nominative subspecies D. concolor concolor, and they are considered junior synonyms of this species. A key to the species of Dilophotopsis is provided. The distributions of Dilophotopsis species, as well as the genetic variation within D. concolor, are associated with individual arid lands, and they indicate that this genus will be useful in the study of the historical biogeography of the North American arid lands.