CHAPTER VII 



FLEAS 

 Pulex irritans, et al. 



PERHAPS by the time that this comes from the printer 

 nearly a hundred and fifty species of fleas will have been 

 found to exist in the world. Something over one hundred 

 are now known and about fifty have been recorded from 

 this country alone. It seems that we are very rich in 

 species of fleas, and, at times, are richer in individuals than 

 we desire. Fleas occur on a great variety of animals. 

 These insects have been found on the dog, cat, rat, squirrel, 

 woodchuck, opossum, grizzly bear, weasel, mole, mice, 

 and other mammals and on birds. Two species, at least, 

 are occasionally serious pests to the domestic fowl and 

 two species attack man. 



THE FORM AND STRUCTURE OF A FLEA 



A flea has a body peculiarly well fashioned for the place 

 in which it has chosen to live. In the first place, its body 

 is compressed, that is, flattened from left to right. When 

 we recall that a flea lives and moves about among hairs set 

 close together we can readily see how much better a com- 

 pressed body is suited for movement among such objects 

 than a wide, flat body would be. In fact, so large an insect 

 as a flea could move with difficulty through a thickly set 

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