any of about 170 species of insects that are delicate, are yellow or brown in colour, have biting mouthparts, and feed on dead plant material. Most species are from 4 to 7 mm (about 0.2 inch) long. Most males have two pairs of narrow wings and are weak fliers, whereas all females are wingless. Webspinners have short, stout legs and run rapidly both forward and backward.

Usually several hundred individuals live together in a colony that is housed in silk-lined chambers and tunnels constructed either beneath stones or among mosses and lichens. Both larvae and adults have silk-producing glands in an enlarged section of the foreleg. When disturbed the webspinner either retreats through its tunnels or pretends to be dead. The female cares for her large cylindrical eggs, often covering them with particles of chewed food.