earwig, common name for any of the smooth, elongated insects of the order Dermaptera. Earwigs are small, with pairs of horny, forcepslike abdominal appendages, larger in the male than in the female, and short, leathery forewings that cover the membranous hindwings when folded. Some of the 900 species lack wings; the winged species rarely fly. Many tropical earwigs are brightly colored and carnivorous, even cannibalistic. The common earwig of temperate climates is native to Europe but has spread widely and seems destined to become cosmopolitan in distribution. Most species feed on plants and some are serious pests; others are predaceous or scavengers. The pincers of the male are used in courtship battles with other males. The female is unusual in that it guards its eggs and tends the young, which molt from 4 to 6 times during metamorphosis. The superstition that earwigs crawl through the ears and into the brains of sleeping persons probably derives from their nocturnal habits and the tarry or waxy odor of a secretion of their abdominal glands. A fossil earwig links the order to ancient cockroaches. Earwigs are classified in the phylum Arthropoda, class Insecta, order Dermaptera.

Any of about 1,100 insect species (order Dermaptera) characterized by large membranous hind wings that lie hidden under short, leathery forewings. Species vary from 0.2 to 2 in. (5 to 50 mm) long, and all are flat, slender, and dark, with a shiny outer covering and simple biting mouthparts. Several species can shoot a foul-smelling liquid, formed in abdominal glands, as far as 4 in. (10 cm). Earwigs have a pair of forceps-like tail pincers (cerci) at the back end of the abdomen that may function in defense, capturing prey, folding wings, or fighting courtship battles.

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