lice [AS, lus,] , any of the small wingless insect order of Phthiraptera. This order has been divided into four suborders: Anoplura (sucking lice), Rhyncopthira, Ischnocere, and Amblycer. Lice are ectoparasites of birds and mammals and may spend their entire life cycle on a single host, attaching eggs to the hair shafts or feathers. They transfer to humans by direct contact. Three forms that infect humans are the head louse, Pediculus humanus capitis; the body louse, Pediculus humanus corporis; and the crab louse, Phthirus pubis. See also pediculosis.
