The Probert Encyclopaedia of Nature

GADFLY

Gadfly is a name commonly applied to various insects, a large number of which belong to the great Linnaean genus OEstrus, while others belong to the genus Tabanus. OEstrus bovis or ox gadfly (the Hypoderma bovis of some naturalists) is about 7 lines in length with a yellow thorax, with a black band; white abdomen; fulvous terminal segments and dusky wings. This species attacks the horse also, the female depositing her eggs in the skin of these animals in considerable numbers. In a short time the eggs are matured, and produce a larva or worm, which immediately pierces the skin, raising large lumps or tumours filled with pus, upon which the larva feeds.

Oestrus equi (the Gastrophilus or Gastrus equi of some naturalists) deposits its eggs upon such parts of the skin of horses as are subject to be much licked by the animal, and thus they are conveyed to the stomach, where the heat speedily hatches the larvae, well known under the name of botts.

Oestrus ovis (also called Cephalomyia ovis) deposits its eggs in the nostrils of sheep, where the larva is hatched, and immediately ascends into the frontal sinuses, attaching itself very firmly to the lining membrane by means of two strong hooks situated at its mouth. Other species infest the buffalo, camel, stag, etc. Even rhinoceroses and elephants are said not to be altogether exempt from their attacks.

The characteristics of the genus Tabanus are two enormous eyes, usually of a greenish-yellow colour rayed or spotted with purple, antennas scarcely longer than the head, the last joint with five divisions. These insects suck the blood of horned cattle, horses, and sometimes people. The Tabanus bovinus, or larger gadfly is common in Europe. It is about 25 mm long, brown above and grey below. Its larva live on the ground, and its metamorphosis takes place under the earth but close to the surface.
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