The mydid fly genus Rhaphiomidas contains fewer than 30 species/subspecies, all of them occurring in the desert regions of the southwestern United States and adjacent portions of northwestern Mexico. The adults are most commonly encountered in sand dune areas, and are typically only active for a few weeks each year, either in the spring or the fall; in some cases, more than one species can occur in the same dune system, but they are allochronic, each flying in different seasons. Almost nothing is known about their biology, though eggs or early instar larvae of some species are laid on the soil surface and appear to be attractive to ants, and are brought into the ant nest (it therefore seems likely that the larvae are predators of the ant brood).
The Rhaphiomidas fly genus includes fewer than 30 species/subspecies found in desert regions of southwestern United States and adjacent parts of northwestern Mexico. Adults are commonly observed in sand dune areas and are active for only a few weeks each year, typically during spring or fall; occasionally, multiple species coexist within the same dune system but fly at different times. Very little is known about their biology, with some species laying eggs or early instar larvae on the soil surface that attract ants and may be taken into ant nests (indicating they could prey on ant broods).