RICINUS. INSECTS. 247 



II. Maxillary palpi not apparent ; antennae filiform. 

 Gen. NIRMUS, TRICHODECTUS. 



Gen. ]. RICINUS, Lat. Pediculus, Lin. 

 Mouth inferior, and composed externally of two lips and two 

 hooked mandibles ; tarsi very distinct, jointed and terminat- 

 ed by two equal hooks ; antennae thickest at their extremity. 



With the exception of one doubtful species, that of the dog, all the other species 

 of Ricini are found exclusively on birds. Their head is generally large, sometimes 

 triangular, sometimes of a crescent shape, and often with angular projections ; but dif- 

 fers sometimes in the sexes, as well as the form of the antennae. M. Latreille perceived 

 in many two smooth approximated eyes on each side of the head ; and according to 

 M. Savigny, they have jaws with a very small palpus upon each of them, conceal- 

 ed by the lower lip, which has also organs of the same kind. They have besides a 

 kind of tongue. Minute fragments of the feathers of birds have been observed in 

 their stomach ; and De Geer found blood in this viscus. In confirmation of this 

 last fact, it has been noticed that these insects cannot live long on dead birds. 

 They are then seen walking restlessly on the feathers, particularly on those of the 

 head and beak. Redi has rudely represented a great number of species. Some 

 have the mouth situated near the anterior extremity of the head, and the antennae 

 inserted at the side, distant from the eyes, and very small. In others the mouth is 

 almost central, the antennae placed very near the eyes, and their length almost equal 

 the half of the head. 



R. corvicoracis, Lat. Whitish, with transverse brown bands on the 

 back, and very short antennae. Found on the Crow. Lat. Gen. i. 

 167. 



FAMILY II. SIPHCJSCULATA, Lat 



Destitute of mandibles, the mouth consisting of a rostrum, from 

 which a syphon or sucker is protruded at will. 



I. Thorax very distinct ; the six feet terminated in a kind of forceps. 



Gen. PEDICULUS H^EMATOPINUS. 



II. Thorax very short, almost none ; body as formed nearly of a head and abdomen ; 

 two anterior feet monodactyle, the others didactyle. 



Gen. PTHIRUS. 



Gen. 2. PEDICULUS, Lin. Lat. 



Body apterous ; head distinct ; thorax bearing six feet ; two 

 antennae ; two eyes with distinct facets ; mouth consisting of 

 a rostrum, inclosing an exsertile sucker ; no mandibles or jaws, 

 properly so called. 



The Insects of this genus have an oval flattened body, covered with a coriaceous 

 skin on the margins, semitransparent and soft in the middle, and furnished at the 

 anterior part with a fleshy papilla inclosing a sucker. The thorax is almost square, 

 and bears six feet of equal size, terminated by a strong scaly hook in place of tarsi, 

 which bending upon a small tooth or point which terminates the leg, enables the 

 animal to crawl on the hair of animals. The abdomen is rounded, oval, or oblong, of 

 eight segments, provided with sixteen stigmata, and scaly at the end in both sexes. 

 All the species of lice live on the blood of the mammalia, which they suck with their 

 proboscis, which, however, is never perceived but when in use. There is scarcely 

 a quadruped which has not one of the species particular to it, and many have seve- 

 ral. Man is attacked by three species. Lice are oviparous animals, and multiply 

 greatly. They deposit their ova, known by the name of nits, upon hair and clothes. 



P. humanus, Lin. Body oval, lobed, of a dirty white colour, with- 

 out spots ; the divisions of the abdomen less projecting than in 

 the following Lat. G en. i. 168. 



