BIRD-LOUSE, any small flattened degenerate wingless insect of the suborder Mallophaga of the order Anoplura (see INSECTS ) parasitic upon birds and mammals and living upon feathers, hair, and other epidermal products. Their biting mouth-parts serve to distinguish them from true lice of the suborder Siphunculata, in which the mouth-parts are suctorial (see LousE).