G34 



THE MICROSCOPE. 



the body may be seen small circular dots, the breathing 

 apertures, with which all the class are freely provided 

 rendering them very tenacious of life, and difficult to kill. 

 There is another louse, rather differing in its characteristics 



Pig. 2S9. 



1, Dog's parasite. 2, Rat Acarus. 3, Head of Cat-Flea. 4, Larva, or. grub ol 

 Flea. (The life size of each is given in the small circles.) 



