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MANUAL OF ELEMENTARY ZOOLOGY 



each moult, and become adult in about a dozen weeks, 

 the time depending upon the temperature and amount of 

 food. Bugs can live for more than a year without food. 

 They have been accused of transmitting the organisms 

 which cause various diseases, but the evidence of this is 

 not convincing. They may best be exterminated by fumi- 

 gation with sulphur after sealing the infected building, or by 



Fig. 195. — The Body Louse (Pediculus vestimenti). 

 In dorsal view. — From Nuttall. 



applying paraffin to walls, etc., in such a way as to work it 

 into all crevices. Lice differ from the bug in lacking any 

 vestige of wings and having the segments of the thorax 

 indistinct. They are smaller, and more dependent on their 

 host, separated from which they soon die. Pediculus 

 vestimenti, the Body Louse, and P. capitis, the Head Louse, 

 live respectively in the clothing and the hair of the head. 

 They have a life-cycle of about six weeks and need constant 

 feeding. They are acquired by contact of person or 



