CEREAL PESTS INSECTS 493 



blending of flour in blending plants the larvae are bolted out 

 by thousands and cites one instance where 1460 worms were 

 taken from one 140-pound bag of straight-grade flour. 



536. Three other grain beetles are often found feeding 

 on grain and mill products, but are not so important as 

 those just described. The foreign grain beetle (Cathartics 

 advena, Waltl.), though occurring in grain and cereal 

 products, does not become a pest when these materials 

 are stored in places dry, clean, and well aired. TKe~s7rtmre- 

 necked grain beetle (Cathartus gemellatus, Duv.) is more 

 common in the southern states, where it is particularly 

 an outdoor species, but is found on grain in the middle 

 Great Plains. The flat grain beetle (Lcemophlceus 

 minutus, Oliv.) is really more often found in flour than in 

 grain, but does not usually occur in sufficient numbers to 

 be a serious pest. 



537. The yellow meal-worm (Tenebrio molitor, Linn.). 

 - This insect is a native of the Old World, but is now 



common in this country, wherever grain is stored. It 

 requires one year for its life cycle. The beetles are noc- 

 turnal, and breed in dark corners, in cracks, and under 

 sacks. They prefer refuse, especially if damp or slightly 

 soured, accumulated in corners, under machinery, in base- 

 ments and other undisturbed places. 



The white bean-shaped eggs are deposited in the spring singly 

 or in groups in meal or grain, which serves as food for the larvae. 

 The larvae are hatched in 2 to 3 weeks, are at first pure white, soon 

 changing to waxen yellow, and are fully grown in 3 to 4 months, 

 when they become long, slender, cylindrical, appearing waxen, and 

 resemble wire-worms. They are then yellow, shading to yellowish- 

 brown toward each end and at each articulation. The tail termi- 

 nates in 2 spines. This form continues until the next spring, when 

 it changes into a white pupa, in which condition it remains 2 to 3 

 weeks, and then changes to the adult insect. 



