182 THE BOOK OF WHEAT 



while in the colder parts of the temperate zones they pass an 

 artificial or domestic existence. Not only do they occasion 

 loss in weight, but the grain which they infest is unfit for con-- 

 sumption either by man or by most animals, and cannot be used 

 profitably for seed. Three species of insects injuring stored 

 wheat pass their adolescent stages within the kernel and are 

 universally the most injurious forms. They are the rice and 

 granary weevils and the Angoumois grain moth. 



The Granary Weevil (Calandra granaria L.). From the 

 earliest times this weevil was known as an enemy to stored grain. 



It became domesticated ages ago, 

 lost the use of its wings, and is 

 now strictly an indoor species. 

 After the grain of wheat is punc- 

 tured 03^ the snout of the female, 

 an egg is inserted. The resulting 

 larva makes room for its transfor- 

 GRANARY WEEVIL, ADULT mations within the kernel by de- 

 AND LARVA. ENLARGED vouring the mealy interior. The 

 grains of most cereals are inhabited 



by a single larva, but several individuals can thrive in a 

 kernel of maize. The length of the life cycle and 

 the number of generations annually produced depend on 

 season and climate. In southern United States there may be 

 six or more generations per year. One pair is estimated to 

 produce 6,000 descendants in a single year. Besides wheat, 

 they attack all the other grains, and the chick-pea. The greatest 

 damage is caused by the long-lived adults, which gnaw into the 

 kernels for food and shelter. 



The Rice Weevil (Calandra oryza L.) resembles the granary 

 weevil in structure and habits. It differs from the granary 

 weevil most essentially in having well developed wings, and 

 consequently being often found in the field. It lays its eggs 

 in the standing grain in the tropics, and in the extreme south 

 of the United States, where it is erroneously called tl black 

 weevil. " It originated in India, was first found in rice, and is 

 now established in most of the grain growing countries of the 

 world. 



The Angoumois Grain Moth (Sitotroga cerealella 01.). Since 

 1736 the injuries of this moth have been noticed in the province 



