ORDER PARASITA. 149 



infancy. These insects constantly live on the same quadru- 

 peds, and the same birds, or at all events, on animals of 

 those classes, which have analogous characters and habits. 

 One bird frequently breeds two sorts. Their motion, in 

 general, is rather slow. 



Some ( Pediculea, Leach,J such as, 



The Lice proper, Pediculus, T>eg. 



Have for mouth a very small nipple, tubular, situated at the 

 anterior extremity of the head, in the form of a muzzle, and 

 inclosing in the state of inaction, a sucker. Their tarsi are 

 composed of an articulation, whose thickness almost equals 

 that of the leg, terminated by a very strong claw, folding 

 back on a tooth-formed prominence of the leg, and perform- 

 ing with this point the office of a pincers. Those which I 

 have observed, have but two smooth eyes, one on each side. 



There are three sorts of them peculiar to man. Their 

 eggs are known under the name of nits. 



In the two following species, the thorax is very distinct 

 from the abdomen, in its breadth and medial length. They 

 form the genus pediculus, properly so called of Dr. Leach. 



The human body-louse, (P. humanus corporis, De G. 

 Insect, VII. 1. 7)- Of ^ dirty white without spots, with 

 the sections of the abdomen less projecting than in the fol- 

 lowing. It comes solely on the body of man, and breeds to 

 a terrific extent in the pediculary disease. 



The human head-louse (P. humanus capitis, De G. In- 

 sect, VII. 1. 6). Ash-coloured, with spaces wherein are 

 situated brown or blackish stigmata; lobes or sections of 

 the abdomen rounded ; on the head of man and particularly 

 of children. 



The males of this species and the preceding have, at the 

 posterior extremity of their abdomen, a small scaly and 

 conical piece, formed like a sting, probably the sexual organ. 



The Hottentots, the negroes, and different Simiae, eat lice, 



