A parasitic insect, Pediculus humanus capitis, which lives among the hairs on the head of a human and feeds on blood.

A parasitic insect, Pthirus pubis, that lives amongst the pubic hairs of humans and feeds on blood.

A kind of parasitic insect on sheep.

A jumping plant louse of the family Psyllidae, of many species.

(obsolete) Any insect of the family Coccidae, that infest the bark of trees and vines. / Any insect of the order Psocoptera, that live on or near trees and feed on algae and lichen.

Any copepod within the family Caligidae (order Siphonostomatoida); a kind of marine ectoparasite that feeds on the mucus, epidermal tissue and blood of fishes.

A parasitic amphipod crustacean of the family Cyamidae found in skin lesions, genital folds, nostrils and eyes of marine mammals of the order Cetacea, i.e. whales, dolphins and porpoises.

Any louse of the suborder Anoplura.

Any true louse that is not a sucking louse; a mallophagan.

A small crustacean of the family Argulidae, parasitic on fishes.