"weevil'' in grain. 161 



their habit of web-spinning that renders them so injurious 

 where they obtain a foothold. Upon attaining full growth 

 the caterpillar leaves its originrJ silken domicile and forms 

 a new web, which becomes a cocoon in Avhich to undergo 

 its transformations to pupa and imago. It is Avhile search- 

 ing for a suitable place for transformation that the insect 

 is most troublesome. The infested flour becomes felted 

 together and lumpy, the machinery becomes clogged, 

 necessitating frequent and prolonged stoppage, and result- 

 ing in a short time in the loss of thousands of dollars in 

 large establishments/'* 



The life-cycle of this insect requires ordinarily about 

 two months, but may be completed in thirty-eight days 

 under the most favorable conditions. The adult moth 

 measures a little less than an ioch across the expanded 

 wings. The fore wings are of a lead -gray color, with 

 transverse black markings, while the hind wings are dirty 

 whitish, with a darker border. 



The Indian Meal-moth {Ploclia interpiDictella Hbn.) 

 (Fig. 92) larvae resemble those of the grain-beetles in 

 having a special liking for the embryo of wheat-grains. 

 They spin a fine silken web as they go from seed to seed, 

 to which they become attached, and to wliieh is added a 

 large amount of excrement, thus spoiling for food much 

 more grain than is actually injured. 



The moth has a wing-exjDanse of an inch; the inner 

 third of the fore wings being a whitish gray, and the outer 

 portion reddish brown, with a coppery lustre. 



The Meal Snout-moth {Pyrcdis farinalis Umn.) (Fig. 

 93) is of a light-brown color, the thorax, base, and tips of 



*"Sorae Insects lujurious to Stored Grain," U. S. Dept. Agr., 

 Farmers' Bulletin, No. 45, F. H. Chittenden. 



