Black flies (Diptera: Simuliidae) are small blood-sucking insects of medical and veterinary importance. Some species are well-known as vectors of the filarial parasite, Onchocerca volvulus, which is responsible for human onchocerciasis. They are also vectors of some blood protozoa of animals. Furthermore, black fly bites on humans can cause rash, dermatitis, localized swelling, itching and pain at the biting site.