Order and Family:
Tabanidae, Horse and Deer Flies
3/4-1 1/8″ (20-28 mm). Jet black. Thorax has fine whitish, yellowish, or black hair. Abdomen has bluish luster. Hind tibiae do not have spurs. Wings are brownish to black, unpatterned. Larva is white with black bands.
Male drinks honeydew and nectar; female sucks blood from large mammals, especially cattle, horses, mules, and hogs. Larva preys on small aquatic insects.
Female attaches egg masses to plants overhanging fresh water. Larvae drop into water, feed, and then overwinter in mud for 2 winters, pupating in spring. Males have very short life-spans; females survive until fall.
Horse flies breed near freshwater habitats but may travel long distances in search of blood meals.
Quebec south to Florida and Gulf states, west to New Mexico, north to Pacific Northwest.
Horse flies are large, robust insects that usually circle an intended victim several times before settling for a blood meal. They buzz loudly in flight and as their name implies, may often be found around horses and other livestock. Horse fly larvae are found near the margins of ponds, swamps and other freshwater habitats. Females feed on mammal blood, they locate victims by tracking the carbon dioxide produced by respiration. This is why you might see them hovering around automobile exhaust pipes. Scientists that study these flies take advantage of this behavior when trapping them for study, traps are baited with dry ice (frozen carbon dioxide).
Warning: This horse fly lands on it’s victim’s neck, head, or back, quickly slices the skin with its blade-like mouthparts, and sucks out blood. Some animals become seriously weakened if they suffer repeated attacks and loss of blood.