PEDICULUS VESTIMENTI 



533 



each provided with a pair of stigmata. The thorax is as broad as the 

 abdomen. Eggs o % 6 mm. in length; about fifty are deposited by a 

 female head louse. The young can propagate when eighteen days old. 



The head louse lives especially in the hairy parts of the head 

 of human beings ; more rarely it is found on other hairy parts 

 of the body. It is spread over the entire surface of the globe, 

 and was present in America before the arrival of Europeans. 

 Quite exceptionally it is said that it bores itself deep into the 

 epidermis and can live in ulcers. 



[The eggs are pear-shaped and are attached to the hairs 

 near the roots by means of a clasping collar. They hatch 

 in about seven days. The young are like the adults and 

 mature in a month. Its general colour varies with that of 

 its host. In West Africans nearly black, in Hindoos dark and smoky, on Chinese 

 and Japanese yellow, on Hottentots orange, on South American Indians dark brown 

 (Murray). F. V. T.] 



FIG. 374. Mouth 

 parts of Pediculus 

 vestimenti. En la rged . 

 (After Denny.) 



FIG. 375. Ovum 

 of the head louse. 

 70/1. 



FIG. 376. Head louse, male. 15/1 



FIG. 377. Pediculus -vesti- 

 menti, Burm. : adult female. 



15/1. 



Pediculus vestimenti, Nitzsch, 1818. 



The head in front is somewhat rounded. Antennae longer than 

 in the head louse ; 2 to 3-5 to 4 mm. in length ; whitish-grey ; the 

 abdomen is broader than the thorax; stigmata as in P. capitis. 

 Eggs 07 to 0-9 mm. in length ; about seventy are deposited. 



P. vestimenti lives on the neck, throat and trunk of persons, and the clothing next 

 the body, in which also the eggs are deposited. The louse of so-called pedicular 

 disease (P. tabescentimn) is, according to Landois' researches, only the usual 

 P. vestimenti; moreover, many cases of phthiriasis are attributable to mites 

 or fly maggots. 



[This parasite has often been a great pest amongst soldiers during long 

 campaigns, especially amongst the Russians during the Crimean War. Vide also 

 notes in Addenda (p. 615) under " Body, Head and Clothes Lice." F. V. T.] 



