Warble fly is a type of large, hairy fly that resembles a bumble bee. Warble flies belong to a group of flies called bot flies (see Bot fly). The larvae (young) of warble flies live under the skin of animals. The cattle warble, or heel fly, usually lays its eggs on the hairs of the feet or legs of cattle. The larvae, called cattle grubs, work their way through the skin of the animal. Under the skin of the back, the larvae cause painful swellings, called warbles.
