Earwig (Forficula), a well-known genus of insects, often ranked along with cockroaches, &c., in the order Orthoptera, but better kept apart to form, along with a few related genera, the order Dermaptera. As important general characters, the following may be noted: the two pairs of wings are very dissimilar, the anterior pair being short and horny (hemi-elytra), the posterior pair folded longitudinally and transversely; the mouth parts are well developed and suited for biting; the antennæ are thread-like; there is no true metamorphosis in the life-history.
The common earwig (Forficula auricularia) is best known for the pincer-like organ at the end of the abdomen. The two component parts possibly represent a pair of persistent abdominal appendages. The forceps are larger (in some forms very markedly) and more curved in the males. The hind pair of wings serve for occasional flight; they are much larger than the firm front pair, and are folded when at rest in a complex way, not only like a fan but also transversely. When folded up they are almost completely covered by the anterior pair. The mobile abdomen is used in folding the wing together. The shape of the expanded hind-wings is somewhat ear-like, and this has given origin to the etymology which regards earwig as equivalent to earwig. In a few forms the wings degenerate.
Earwigs avoid the light, and do most of their work in the dark. They feed, as gardeners well know, on petals and other parts of flowers, on fruit, seeds, and leaves, nor is animal debris refused. They are usually and readily caught in artificial shelters provided for their destruction. They are very sensitive to tobacco smoke. During the day they shelter underground or under stones and bark. In spite of their names—earwig, Ger. Ohrwurm ('ear-worm'), Fr. Pierce-oreille ('pierce-ear'); the Armenian name also means 'ear-enterer'—they are not known to enter the ears of sleepers.
The eggs of the common species are laid in spring, fifteen to twenty, in some convenient cavity. These are carefully watched, and even after the birth of the young earwigs, the mother still tends them as a hen does her chicks.
The distribution of the common earwig is very wide, and the same is true of the order. The largest European species (F. gigantea) measures about an inch in length. A little earwig (Labia minor) is common in Britain and elsewhere, and may be often seen flying on warm summer afternoons. In the genus Chelidura the hind-wings are lost, and the front pair rudimentary. Labidura is another important genus.