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Horse-flies (for other names, see common names) are true flies in the family Tabanidae in the insect order Diptera. They are often large and agile in flight, and the females bite animals, 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. Adult horse-flies feed on nectar and plant exudates; the males have weak mouthparts and only the females bite animals to obtain enough protein from blood to produce eggs. The mouthparts of females are formed into a stout stabbing organ with two pairs of sharp cutting blades, and a spongelike part used to lap up the blood that flows from the wound. The larvae are predaceous and grow in semiaquatic habitats. Female horse-flies can transfer blood-borne diseases from one animal to another through their feeding habit. In areas where diseases occur, they have been known to carry equine infectious anaemia virus, some trypanosomes, the filarial worm ''Loa loa'', anthrax among cattle and sheep, and tularemia. As well as making life outdoors uncomfortable for humans, they can reduce growth rates in cattle and lower the milk output of cows if suitable shelters are not provided. Horse-flies have appeared in literature since Aeschylus in Ancient Greece mentioned them driving people to madness through their persistent pursuit. Shakespeare uses the theme of the maddening gadfly in his plays ''King Lear'' and ''Antony and Cleopatra''. ==Common names== Apart from the common name "horse-flies", broad categories of biting, bloodsucking Tabanidae are known by a large number of common names. The word "Tabanus" was first recorded by Pliny the Younger and has survived as the generic name. In general, country-folk did not distinguish between the various biting insects that irritated their cattle and called them all "gad-flies", from the word "gad" meaning a spike. The most common name is "cleg", "gleg" or "clag", which comes from Old Norse and may have originated from the Vikings. Other names such as "stouts" refer to the wide bodies of the insects and "dun-flies" to their sombre colouring. ''Chrysops'' species are known as "deer-flies", perhaps because of their abundance on moorland where deer roam,〔 and "buffalo-flies", "moose-flies" and "elephant-flies" emanate from other parts of the world where these animals are found.〔 In North America they are known as "breeze-flies", and in Australia, some are known as "March flies", a name used in other Anglophonic countries to refer to the non-bloodsucking Bibionidae. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Horse-fly」の詳細全文を読む スポンサード リンク
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