114 PHYSIOLOGY AND NATIONAL NEEDS 



grammes of wheat on April lOtli, 1918. By July 

 15tli the number of live adults had dropped to 80/ 

 but by September 3rd it had increased to 2203. 

 This species is generally believed to be indigenous 

 in countries with cooler climates than those of which 

 the rice- weevil is a native, and is accordingly more 

 likely to become troublesome in Great Britain under 

 ordinary temperature conditions. 



It is quite clear from these results that in our 

 own climate multiplication only takes place in the 

 warmer months of the year — except in places that 

 are artificially heated — hence one of the reasons for 

 keeping grain-stores as cool as possible. In warm 

 weather, however, it is obvious that the rapid mul- 

 tiplication of the weevils is a source of great danger, 

 and the danger is naturally greater in climates like 

 those of India, Australia, and South America. 



There can be no doubt that a certain amount 

 of moisture in the wheat — say from 8 to 16 per cent 

 or thereabouts — is also necessary for the mainte- 

 nance of the weevils in a flourishing condition, and 

 much stress has very properly been laid upon the 

 importance of keeping the wheat as dry as possible 

 in order to prevent " weevilling." Unfortunately, 

 however, wheat is a very hygroscopic substance 

 and readily absorbs moisture in damp weather, so 

 that the problem of keeping it dry is not altogether 

 a simple one, while, on the other hand, the weevils 



* Possibly 83, as only 17 were found dead. 



