Horse-flies and deer flies are true flies in the family Tabanidae in the insect order Diptera. The adults are often large and agile in flight. Only female horseflies bite land vertebrates, including humans, to obtain blood. They prefer to fly in sunlight, avoiding dark and shady areas, and are inactive at night. They are found all over the world except for some islands and the polar regions. Both horse-flies and botflies (Oestridae) are sometimes referred to as gadflies.
Deer flies are bloodsucking insects considered pests to humans and cattle. They are large flies with large brightly coloured compound eyes, and large clear wings with dark bands. They are larger than the common housefly and smaller than the horse-fly. There are 250 species of deer fly in the genus Chrysops. Their distribution is worldwide, though they have not been reported in Iceland, Greenland, or Hawaii.
Tabanus bovinus, sometimes called the pale giant horse-fly, is a species of biting horse-fly. As the scientific name suggests, it prefers bovine animals as the source of blood, although it may bite other kind of mammals as well. The insect is relatively large for a horse-fly, adults usually being 25–30 mm long. Like most other horseflies, its compound eyes are very colorful with stripe-like patterns. Its body and wings are mostly colored brownish gray. It is quite fast and an able flier, being capable of evading most attempts to swat it with ease. It bites humans infrequently, because of its preference of bovine animals. This loud-buzzing horse-fly can be a nuisance, as it circles around its target and occasionally lands to deliver a bite. However, to humans it is considerably less harmful than deer flies (Chrysops), which bite much more vigorously.
Tabanus is a genus of biting horseflies of the family Tabanidae. Females have scissor-like mouthparts that are able to penetrate the skin of livestock animals. The horsefly can then extract and ingest the animal's blood. Horseflies of this genus are known to be potential vectors of anthrax, worms and trypanosomes. Some species, such as Tabanus bovinus, prefer bovine animals and are less harmful to humans. The genus contains hundreds of species and many species groups.
Chrysops niger, the black deer fly, is a fly of about 8–10.5 millimetres (0.31–0.41 in) length, with a mostly black body with some white hairs, and having wings which are barred with black. They are active from May to September around areas of marsh.
Tabanus glaucopis, also known as the downland horsefly, is a species of biting horse-fly.
Tabanus maculicornis also known as the narrow-winged horsefly is a species of biting horse-fly.
Tabanus sudeticus, also known as the dark giant horsefly, is a species of biting horse-fly. It is the heaviest fly in Europe.
Tabanus spodopterus also known as the black horned giant horsefly is a species of biting horse-fly. It is widespread in Europe, but only one doubtful specimen has been found in the United Kingdom.
Chrysops relictus, the twin-lobed deerfly, is a largish European and Asian deerfly of about 8–10.5 millimetres (0.31–0.41 in) length. The larvae feed upon organic matter in damp soils, and are termed hydrobionts in that they inhabit areas of high water content.
Haematopota pluvialis, the common horse fly or notch-horned cleg fly, or simply cleg in Scotland and northern parts of Ireland, is a species belonging to the family Tabanidae subfamily Tabaninae.
Philipomyia aprica is a species of horse fly of the family Tabanidae, subfamily Tabaninae.
Haematopota crassicornis, the black-horned cleg is a species in the horse-fly family, Tabanidae.
Hybomitra montana, the slender-horned horsefly, is a species of horse flies in the family Tabanidae.
Diachlorus ferrugatus, commonly known as the yellow fly in the United States or doctor fly in Belize, is a species of highly aggressive biting horse-fly of the family Tabanidae native to North and Central America to Costa Rica.
Chrysops viduatus is a species of 'horse flies' belonging to the family Tabanidae.
Chrysopsinae is an insect subfamily in the family Tabanidae commonly known as deer flies or sheep flies and are bloodsucking insects considered pests to humans and cattle. They are large flies with large brightly-coloured compound eyes, and large clear wings with dark bands. They are larger than the common housefly and smaller than the horse-fly.
Chrysops flavidus is a species of deer fly in the family Tabanidae. The species is identifiable by its yellow legs.
Hybomitra distinguenda is a Palearctic species of horse fly in the family Tabanidae.
Hybomitra expollicata, also known as the striped horsefly, is a Palearctic species of horse fly in the family Tabanidae.
