INSECTS AND OTHER SMALL ANIMALS 



Weevils are also found in flour and often infest flour milis. The 

 only practical method of killing them in flour mills is to use hydro- 

 cyanic acid gas. This gas is fatal to all animal life, and should be 

 used only with the utmost caution and by those who understand the 

 proper method of using it. The mill or room to be fumigated is closed 

 tightly and arrangements made for properly ventilating it without en- 

 tering it after the fumigation is complete. One ounce of cyanide 

 of potash is used for each one hundred cubic feet to be fumigated. A 

 four-gallon crock containing five pounds of sulphuric acid and seven and 

 one half pounds of water should be left in the room. Just before leaving, 

 three pounds of cyanide of potash done up in a paper package should 

 be dropped into the crock. One should then leave the room quickly, 

 closing the door. The fumigation should proceed for not less than 

 twenty-four hours. Ventilate the room or building thoroughly before 

 reentering. 



The Mexican Cotton Boll Weevil. This beetle from 

 Mexico has spread over large portions of the cotton- 

 growing sections of the south, doing great damage. 



FIG. 153. Mexican Cotton Boll Weevil. 

 Much enlarged, above ; natural size, below. (Herrick.) 



