9 2 



Illustrated Studies 



FIG. 173. Metamorphosis of flea. 



FlG. 172. Metamor- 

 phosis of house fly 

 (enlarged). 



FIG. 174. Louse and 

 its eggs attached to a 

 hair. Natural size 

 and magnified. 



FIG. 175. Bed bug. x 5. 



FIG. 176. Life history of mosquito. 



