Black fly (Simuliidae)
Learn more about blackfly with a free trial on Britannica.com.
Any member of several species of small dipterans, most of which bite or annoy humans. Midges are also sometimes called gnats. In North America the name is also applied to the blackfly, fruit fly, and other small flies that hover about the eyes of humans and other animals.
Learn more about gnat with a free trial on Britannica.com.
The males often assemble together in large mating swarms, particularly at dusk, called a "ghost".
Gnat larvae are mostly free-living and some are aquatic. Many feed on plants, though some are carnivorous. Larval plant feeders (e.g. the Hessian fly larva) cause root, stem, or leaf galls to be formed by the host plant. Some species of fungus gnats (families Mycetophilidae and Sciaridae) are very common pests of mushrooms and roots of potted plants in homes and greenhouses.
Occasionally "gnat" is spelled "knat".
Gnats take folks and fowl by swarm: An invasion of biting bugs in central Illinois turns spring's outdoor joys into nightmares.
May 09, 2007; Byline: Bob Secter May 9--PETERSBURG, Ill. -- Swarms of tiny buffalo GNATs were so thick in Todd Knoles' yard last week...