Velvet ants (Hymenoptera: Mutillidae) of the Bitter Lake National Wildlife Refuge were collected and studied over a 4-year period (1996 to 1999). The study resulted in the collection of at least 52 species in 6 genera. It also resulted in the discovery and description of the previously unknown male of Dasymutilla calorata Mickel, plus the discovery and description of 2 new species.