INSECT CONTROL IN FLOUR MILLS. 5 



in turn are matted together by the burrowing and crawling larvse. 

 Finally the webbed masses (fig. 3) become so large that they choke or 

 clog the machinery and force the miller to shut down. There is then 

 nothing left for the miller to do but set his men to a thorough clean- 

 ing out of all machinery, spouts, etc. 



HOW MILLS BECOME INFESTED. 



The Mediterranean flour moth gains access to the majority of mills 

 through the medium of secondhand or returned sacks. The moths oc- 

 cur in blending plants, where they lay eggs on old sacks, and the lar- 



Fig. 2.- — An adult Mediterranean flour moth resting naturally upon a plank. Notice 

 characteristic posture. These moths are so tame and remain so quiet that they" often 

 escape attention. (Dean.) 



vee then hide and spin cocoons in the seams and folds, thus making it 

 easy for the pest to be carried from place to place. The installing of 

 secondhand machinery that has not been properly fumigated is also 

 a means of dissemination. These are the main avenues of entry to 

 uninfested and new mills that any miller can close if he will. The 

 miller is, however, more or less helpless to prevent infestations when 

 his mill is located in a center of general infestation, as the adult moth 

 can fly from building to building. Of course, all returned sacks are 

 apt to bring infestations. 



