Horse-Fly, or Hippolosca, L. a genus of insects, comprising four species : the principal of these is the equina, or Common Horse-fly, which equally torments horses and cows.

The horse-fly is broad, flat, shining, and apparently covered with scales ; its head, breast, and belly, are of a yellowish colour, streaked with brown. These in-sects are very difficult to be killed, on account of the hard scaly wings with which they are covered; and so firmly do they adhere to the poor animals, that these can neither rub nor bite such pernicious vermin off their skin, without severely wounding themselves. Hence the only preventive we can devise, is a net for covering the horse in hot weather, or in travelling through woods, or such places as are infested with these troublesome flies.