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.