Black flies or blackflies (sometimes called buffalo gnats, turkey gnats, or white socks) are flies in the family Simuliidae of the Culicomorpha infraorder. Simuliidae are related to the Ceratopogonidae, Chironomidae, and Thaumaleidae. Over 2,200 species of black flies have been formally named, of which 15 are extinct. They are divided into two subfamilies: Parasimuliinae contains only one genus and four species; Simuliinae contains all the rest. Over 1,800 of the species belong to the genus Simulium.
Black flies are usually small, black or gray, with short legs and antennae. They feed mainly on nectar for flight energy, and the females of most species also gain nourishment for egg production by feeding on the blood of birds or mammals, including humans. They are a common nuisance for humans, and many U.S. states have programs to suppress the black fly population. They spread several diseases, including river blindness in Africa (Simulium damnosum and S. neavei) and the Americas (S. callidum and S. metallicum in Central America, S. ochraceum in Central and South America).
