9 2 



Illustrated Studies 



Fig. 171. 



%£&% 



FIG. 173. — Metamorphosis of flea. 



a 

 FlG. 172. — Metamor- 

 phosis of house fly 

 (enlarged). 



Fig. 175. — Bed bug. x 5. 



Fig. 176. — Life history of mosquito. 



