492 THE SMALL GRAINS 



pupal stage. The pupae are frequently in cracks or crevices of the 

 bin, and may be overlooked. In 6 to 12 days the adult beetles 

 emerge. These are very small, slender, flattened, dark brown, 

 1*0 inch long, having the thorax armed on each side with 6 saw-like 

 teeth. They are very active and run away quickly when dis- 

 turbed. In middle latitudes there are 4 to 6 generations annually. 

 The life cycle varies in length from 6 to 10 weeks in spring to only 

 24 to 30 days in midsummer. 



This insect is common in cereal and feed mills, and in 

 warehouses and grocery stores where there are cereals and 

 mill products. Corn bran is often infested, and should 

 not be used for bedding in railway cars (Dean, 1913, pp. 

 202-204). 



535. The cadelle (Tenebroides mauritanicus, Linn.) is 

 widely distributed over the world. Though there is 

 only one generation each year, and the insect is predaceous, 

 nevertheless, it is a serious pest. Both the adult and larva 

 feed on grain, giving special attention to the embryo, and 

 destroy the vitality of many kernels that are not consumed. 

 They are sometimes beneficial by devouring other grain 

 insects. This species is often found in elevators, gran- 

 aries, and cereal mills. 



The larva is a greasy, flattened, somewhat hairy worm, whitish, 

 f inch long, head and tail dark brown, tail ending in two horny 

 points. The adult is a beetle, black, or nearly so, flattened, ^ inch 

 long, oblong, thorax and abdomen loosely joined. The adult and 

 larva are easily distinguished from other stored grain and flour 

 insects. The larva is much larger and more fleshy than other flour 

 worms. The pupa is white. 



In flour mills the adults are found in nearly all parts, 

 and the larva in accumulations at the bottom of elevator 

 boots and flour conveyors. The latter is a common pest 

 in bags of flour. Dean states (1913, p. 206) that in the 



