Order Diptera, family Tabanidae, Tabanus spp.
Adult--1/4" to 1"
Larger than house flies, usually darker with larger eyes. Some horse flies are jet black. Hair is all short and fine, not bristly. Eyes are often brilliantly colored.
Eggs are laid on vegetation in marshy areas. Larvae are predaceous on small insect larvae, worms, and crustaceans.
Flowers, excrement, and decaying organic matter.
Females are animal-blood feeders. Bites are painful. Males eat nectar from flowers.
Horse flies are vectors of several diseases and can be troublesome to livestock and humans.
Control: Fly parasites, flycatchers and other birds. Fly swatters and natural diatomaceous earth fed to animals. Releasing the beneficial insect called the fly parasite, or dump fly, will eliminate any infestation. Citrus oil sprays will also kill them.
These stout, broad-headed flies that are usually dark-colored and often have brightly colored eyes. Their flight is usually silent, unlike that of house flies, and they deliver a painful bite in search of a blood meal. Only the females bite; the males feed on nectar and pollen.
Compost offers powerful biological fly control. Composting organisms like bacteria, fungi, mites, insects, and even small animals add in the decomposition of animal dung and attack immature flies in the manure.
For more information read the Texas Bug Book.