views updated

Phthiraptera (lice; class Insecta, subclass Pterygota) Order of insects which are closely related to Psocoptera, Hemiptera, and Thysanoptera. Lice may be distinguished by the lack of wings and ocelli; the reduction of the antennae to three flagellomeres, scape, and pedicel; the loss of the metathoracic spiracles; and the reduction of the ovipositor. All species are obligate ectoparasites of birds and mammals, feeding on skin debris, feathers, sebaceous exudates, or blood. The eggs are attached to the fur or feathers of the host, and there are three nymphal stages. There is no pupa, and the whole of the life cycle is spent on the body of the host. The order comprises about 3000 described species, in four suborders: Anoplura, Rhyncophthirina, Ischnocera, and Amblycera.