- A dipterous insect of the family (Estridae, of many
different species, some of which are particularly troublesome to
domestic animals, as the horse, ox, and sheep, on which they deposit
their eggs. A common species is one of the botflies of the horse
(Gastrophilus equi), the larvae of which (bots) are taken into the
stomach of the animal, where they live several months and pass through
their larval states. In tropical America one species sometimes lives
under the human skin, and another in the stomach. See Gadfly.