Alternate name: Greenhead Flies

Family: Tabanidae, Horse and Deer Flies view all from this family

Description 3/8-5/8" (9-15 mm). Body somewhat flattened, head smaller than that of horse fly. Black with yellow-green markings on thorax and most of abdomen. Antennae cylindrical. Eyes bright green or gold with zigzag or other patterns. Hind tibiae have 2 spurs at tip. Wings have distinctive brownish-black pattern. Larva is yellowish white or greenish with brown rings.

Warning A deer fly circles over its intended victim's head before settling, then immediately gives a nasty bite.

Food Male drinks plant juices; female sucks blood from mammals. Larva feeds on small aquatic insects.

Life Cycle Shiny black eggs are laid in clusters on leaves of emergent plants just above water. Fully grown larvae pupate in mud at edge of water. Adults emerge May-August.

Habitat Deciduous and mixed forests, meadows, roadsides, and suburbs near water.

Range Throughout North America.

Discussion Some transmit bacteria that cause tularemia in rabbits, hares, and occasionally people. The most common species, the Callidus Deer Fly (C. callidus), has black on its thorax and V-shaped black marks on abdominal segments 2, 3, and 4. It pesters animals and people during June and July, from Maine to Florida, west to Texas, north to British Columbia.