312 



HOUSEHOLD INSECTS 



campaign, inmates of prisons, and other places where the 

 individuals from necessity or neglect fail to wash and 

 change their clothing at frequent intervals, this louse be- 

 comes very abundant and troublesome. Such was the case 

 among the Russian soldiers in the Crimean War; and 

 among our own soldiers in the Civil War, the body lice 

 familiarly called "graybacks," because of the dark color- 

 ing on the back, became 

 abundant and most an- 

 noying. In the campaigns 

 of the Civil War the 

 soldiers had little oppor- 

 tunity to change their 

 clothing, and not much 

 chance to wash it, other 

 than in cold water, which 

 does not kill these lice. 



Leeuwenhoek, one of 

 our very oldest zoologists 

 who worked about 200 

 years ago with great en- 

 thusiasm, made an attempt 

 to find out something 

 definite about the life 

 history and rate of development of the body louse. He 

 did not believe the popular saying that a louse could 

 become a grandfather in twenty-four hours. At first he 

 thought of hiring some person to act as a host for the lice. 

 Later, he changed his mind, overcame his own natural 

 aversion to these pests, and inclosed two large females 

 within a fine black stocking, the top of which he fastened 

 tightly around his leg above the knee. Here he allowed 



Fig. 107. — Body louse. ( X 20.) 



