- any of the minute, black gnats of the dipterous family Simuliidae, having aquatic larvae.
noun plural -flies
- a black aphid, Aphis fabae, that infests beans, sugar beet, and other plantsAlso called: bean aphid
- any small blackish stout-bodied dipterous fly of the family Simuliidae, which sucks the blood of man, mammals, and birdsSee also buffalo gnat
- Any of various small dark humpbacked flies of whom the females are aggressive biters and serve as vectors in the transmission of onchocerciasis.