Chorioptic mange mites have been reared in vitro on epidermal debris. The life history of the mite has been observed, and each stage in the cycle described. Mites from the cow, horse, goat, sheep, and llama have been shown to be identical biologically and morphologically, and the specific names of equi, caprae, and ovis have been synonymized with C. bovis. The in vitro life cycle has been completed on epidermal debris from a variety of wild Cervidae, Bovidae, and Equidae, as well as on material from several breeds of domestic cattle, horses, sheep, and goats. From these and other data, three additional species or subspecies of Chorioptes were synonymized also with C. bovis. Only one other species, namely C. texanus, remains in the genus.