Black Fly

Adult Black Flies are small (usually 1.2 to 3 mm) and dark with short legs. They have a humpbacked shape. Their wings are broad and the antennae are about as long as the head. Male black flies have larger eyes than females. Some species have white markings. Eggs are 0.18 to 0.46 mm long and somewhat irregular in shape. The eggs are pale white at first, and then darken as the embryo matures. Larvae are slender, 5 to 15 mm long, whitish-brown to black and have a distinct head and anterior proleg. Black fly pupae are 2 to 3 mm long with a respiratory organ on the thorax which protrudes from the open end of the cocoon.

They are found in nearly all the streams of North Carolina. Surrounding states are inhabited by one or more species of black flies, particularly areas where water flows rapidly and tumbles, such as pond spillways. Female black flies feed upon people, livestock, poultry, wild birds, and mammals.

Black flies are persistent and irritating pests which swarm around humans and other animals. Black flies get into the nose, eyes, ears, and mouth and crawl into clothing when abundant. On cattle and horses, the ears seem to be the favorite feeding location. Flies lacerate the skin and suck blood from their unfortunate hosts.

Photo courtesy of Clemson University Department of Entomology, Soils & Plant Sciences, Cooperative Extension Service.

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