272 OUR HOUSEHOLD INSECTS 



which has formed its resting-place only a shrivelled skin, 

 which soon falls away. 



The larvae are of similar habits to those of our own 

 flea -, they live on sandy shores, often in great numbers ; 

 and the perfect insects seem also to be normally found 

 in such situations, and their occurrence in houses may 

 perhaps be accounted for by the fact that they do not 

 confine their attention to the human species, but attack 

 various other animals as well. Hence, dogs and mice, 

 both of which are attacked by chigoes in the feet in the 

 same waj^, as man, may be the means of introducing 

 them. This intolerable pest, the worst of all human 

 parasites, has unfortunately been introduced into Africa 

 by commercial intercourse with its headquarters, but it 

 seems unable to spread to districts beyond the tropics. 



