INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



440 



a dose does not appear to kill all of the young and is not a sure 

 exterminator. In the storage bins, one to two pounds of carbon bisulfid 

 to every one thousand cubic feet of air space for forty-eight hours is 



Fig. 458. — Adults of the potato tuber moth. Phthorimopa operculella 

 (Zell.). Enlarged three times. (Author's illustration, Mo. Bui. Cal. 

 Hort. Com.) 



claimed sufficient to kill the eggs, and for fifteen to sixteen hours to 

 kill the larvae in the tubers. Three or four fumigations will not hurt 

 the potatoes, according to the experiments of F. Steward. 317 



In some places crop rotation is advised, and grain, corn, forage crops 

 or beets, beans, etc., are recommended. The rotations should never be 

 for a period less than five or six years. 



THE ANGOUMOIS GRAIN MOTH 

 Sitotrocja cerealella (Olivier) (Family Gelechiidae) 



(Gclcchia cerealella Olivier) 

 (Fig. 459) 



Description. — The adult females are light-yellowish, iridescent- 

 brown, with few darker markings on the front wings. They average 

 about one inch in length, including folded wings. The very small eggs 

 are oval-elongate and slightly pinkish in color. The larva- are scarcely 

 over -] inch long, but more often small enough to comfortably occupy 

 the inside of a wheat or barley kernel. They are robust and white. 

 The pupae are pale yellowish-brown. 



317 Rept. Australia Assn. Adv. of Sri., Vol. XIV, pp. 328, 329. 



20— i.°>oc>4 



