The earwigs are an order (Dermaptera) of insects characterized by large membraneous wings folded underneath short leathery forewings (thus the literal name of the order - "skin wings"). The abdomen extends well beyond the wings, and frequently, though not always, ends in a pair of forceps-like cerci. With about 1,800 recorded species in 10 families, the order is relatively small among the Insecta, but the earwigs themselves are quite common throughout the world, often finding their way into houses, where they are usually first noticed scurrying across the floor.
Most earwigs are elongate and low to the ground, and a dark brown in color. Lengths are mostly in the 10-14 mm range, with a species of St Helena reaching 80 mm. The cerci range from nonexistent, to long arcs up to 1/3 as long as the rest of the body. Mouthparts are adapted for chewing. The hindwings are folded in a complicated fashion so that they fit under the forewings; but despite all the trouble, earwigs rarely fly.
The earwig abdomen is flexible and muscular, and capable of both maneuvering and opening/closing the forceps. The forceps seem to be used for a variety of purposes. Their role in self-defense is familiar to every child whose first grab at a passign earwig resulted in a pinch - more surprising than painful, the forceps not being particularly strong. In some species, the forceps have also been observed in use for holding prey, to unfold the wings, and in copulation.
The name "earwig" is said to originate from an old belief that earwigs crawl into people's ears and lay eggs in the brain. Earwigs do tend to prefer being in hidden places, and it's certainly possible that once upon a time one earwig crawled into the ear of a sleeping person, but that would be a very rare occurrence. Another explanation is that it is an alteration of "ear-wing", after the shape of the hind wings when unfolded.
The Hemimeridae are unusual in that they live in the fur of giant rats and feed on the rats' dead skin and fungi.
- Common earwig Forficula auricularia