Are Black Flies Small?

Black flies are one of the most irritating insects around. There are around 160 species in Canada, and some are known to bite people. They are small, two to six millimeters long, with large eyes and arched thoraxes. They tend to be attracted to bodies of water, and they breed in these areas.

Black flies are aquatic insects that prefer fast-running, clean water. Females lay hundreds of triangular eggs under water’s surface. These eggs are protected by a membrane and are not visible to the naked eye. When mature, they hatch into larvae that resemble worms. Adult black flies are less than half an inch long, and they are shaped like an hourglass.

Adult black flies feed on a variety of host species, including humans and livestock. Their bites are often accompanied by itching and local swellings. They are especially threatening to livestock if they occur in large numbers. If you are bitten by black flies, consult a doctor to determine the cause and treatment of the infection.

Black flies can spread parasites during their blood meal. They typically feed during late spring and early summer. In addition to being nuisances, they can also transmit important human diseases, such as river blindness, to livestock.