498 THE SMALL GRAINS 



and may necessitate a shutting down of the mill until it can be 

 thoroughly cleaned. The pupal stage lasts 8 to 12 days. Under 

 ordinary conditions the entire life cycle is about 9 weeks. The 

 adult moth is small, tame, pale leaden-gray, measures less than 

 1 inch across the expanded wings, and when resting, assumes a char- 

 acteristic slightly elevated position in front (Fig. 156). In well- 

 heated mills there may be 6 or more generations in a year (Dean, 

 1913, pp. 223-228). 



In cool weather this insect will be found more commonly 

 around the warmer parts of the mill machinery. Dean 

 believes from his observations that in a majority of cases 

 " the Mediterranean flour-moth infestation of flour mills 

 has originated through the practice of handling second or 

 return sacks." When a mill becomes infested, the entire 

 building should be fumigated. 



542. The Indian-meal moth (Plodia interpunctella, 

 Hbn.) is another introduced species which is now gener- 

 ally distributed over this country. It feeds on grain, 

 flour, meal, bran, breakfast foods, and various foods and 

 dried materials. It is especially fond of the wheat embryo, 

 and one caterpillar will destroy dozens of kernels for seed 

 purposes. 



The eggs are minute, white, and are deposited singly or in groups 

 of 3 to a dozen or more. They hatch in 4 or more days. The 

 larva, when full grown, is | inch long, and varies in color, being whit- 

 ish with light rose, yellowish, or greenish tints. The pupa is light 

 brown. The adult moth resembles in size and appearance the clothes 

 moth, is almost f inch across the expanded wings, the outer f of the 

 fore wings reddish brown, the inner whitish gray, frequently seen 

 flying about mills, stores, and houses. There are 4 to 6 broods 

 in a year, depending upon the temperature. 



The caterpillar spins thin silken tubes through the ma- 

 terial it feeds on, as does the Mediterranean flour moth, 

 It also fastens together, by web-spinning, various seeds, 



