HEMIPTERA. ^ 



thorax. They are fitted for climbing, being furnished with a pow- 

 erful curved claw at the tip of the tarsus, which is opposed by a 

 toothed projection of the tibia. This arrange- 

 ment is admirably adapted for clinging to hairs. 

 The young do not undergo a metamorphosis. 

 Only a few species pertaining to this family are 

 known. The bird-lice, which differ from the 

 true lice in having biting mouth-parts, consti- 

 tute the family Mallophagidce, of the order 

 Pseudoneuroptera, and should not be con- 

 founded with the insects we are now de- 

 scribing. 



Three species of lice infest man ; these are 

 as follows : 



The head-louse, Pediculus cdpitis. This FlG - "? 



asini. (From Law.) 



is the most common species infesting man. 



It lives in the hair of the head, and is found upon all 

 races of men. It is most common upon the heads of neglected 

 children. Its general color is pale yellowish, with the outer edges 

 of the thorax and abdomen dark brown or gray, and the tarsal 

 claws pale brown. The eggs are oval, and are usually glued by the 

 pointed end to the hair of the host. These " nits" are said to hatch 

 under favorable conditions in about a week from the time they are 

 laid. Under ordinary circumstances, cleanliness and the use of a 

 fine-toothed comb are all that is necessary to insure freedom from 

 this disgusting pest. 



The Body-louse, Pediculus vestimenti. This is somewhat larger 

 than the preceding species. Like the head-louse, it infests all races 

 of men. It is an interesting fact, however, that peculiar varieties 

 have been developed upon the different races. The variety which 

 infests the Whites in this country is yellowish, tinged with gray ; 

 " that of the West African and Australian is nearly black ; of the 

 Hindoo, dark and smoky; of the Africander and Hottentot, orange; 

 that of the Chinese and Japanese, yellowish brown ; of the Indians 

 of the Andes, dark brown ; of the Digger Indians of California, 

 dusky olive ; and that of the more North American Indians, near the 

 Esquimaux, paler, approaching to the light color of the parasites of the 

 European." * This insect lives upon the skin of most parts of the 

 body ; but especially selects the chest and back. It is often trouble- 



* Andrew Murray, Economic Entomology, p. 392. 



