HOUSEHOLD AND CAMP INSECTS 47 



female may lay over lOO eggs in about 30 days. The egg period is 

 about 6 days and the lice require approximately 18 days to attain 

 maturity. The eggs or " nits " are whitish, pear-shaped, and 

 fastened by their smaller ends to the hairs, especially those back of 

 the ears. This parasite is almost entirely confined to the head, 

 though it has been recorded as biting various animals. The restricted 

 habitat makes it relatively easy to control. 



Among school children the judicious use of a fine-tooth comb, 

 or the application of a tincture or extract of larkspur is usually 

 effective. Kerosene, if applied with discretion, will destroy the 

 insects without untoward effects. Beyer *^ recommends putting a 

 strip of parchment 4 to 6 inches broad around the head and fore- 

 head, holding the same with a bandage, and inside the projecting 

 margin placing a well-fitted pad of gauze which is sprinkled with 

 xylol and the whole is then covered by a pasteboard disk. The 

 projecting margin of the parchment is now turned in over the 

 pasteboard top and the entire covering held down by a bandage. 

 The sprinkling may be repeated several times if necessary. Kin- 

 loch *^ states that the destruction of thd pests may be secured in the 

 hospital by going over the hair carefully with pieces of cotton 

 wool moistened with either trichlorethylene or tetrachlorethane, and 

 by this method there is no danger of irritating either the scalp or 

 eyes. Shaving and washing the head of adults, followed by smear- 

 ing with xylol, kerosene, acetic acid or liquid of Malinin, is 

 recommended.*^ 



Crab Louse 



Phthirius pubis Linn. 



The flattened, broad, whitish crab louse is very different from 

 either the head or body louse. Its very stout legs are tinged with 

 red and add greatly to the crablike appearance of the parasite. 

 It lives on all the hairy portions of the body except the head, and 

 under exceptional conditions may be found on the head, though it 

 displays a marked preference for the pubic region and the armpits. 

 The pear-shaped eggs are attached to the hairs and hatch in 6 or 7 

 days, and in 15 days the young lice are mature. This pest will 

 live apart from its host under favorable conditions for 10 to 12 

 hours. 



45 Mil. Surg., 38:486. 1916. 



46 Brit. Med. Jour., 2892, p. 792. 1916. 

 4' Popov. Rev. Appl. Ent, 3:123. 1915. 



