x] Beetles 119 
Grain Weevil. 
Considerable damage is often done to stored grain 
by the larvae of two small beetles, Calandra granaria 
and C. oryzae. They attack all kinds of grain, such as 
barley, malt, wheat, maize, and oats, and are trouble- 
some to cargoes of grain as well as in granaries and 
breweries. The trouble begins in the spring and 
summer. The beetle bores a small hole in the grain 
by means of its snout or proboscis; into this hole it 
proceeds to deposit an egg and then closes the hole with 
saliva. One egg is deposited in each grain and in this 
way a lot of grains are infected by a single beetle. 
The larva which hatches from the egg feeds on the 
grain, devouring all except the skin and the germ. 
When it has eaten its fill it changes to a pupa and 
shortly afterwards into the adult beetle. This then 
eats its way through the husk, leaving a large hole 
(see Fig. 34b). The time taken to complete the life 
cycle depends largely on the temperature. Under 
favourable conditions such as a close atmosphere this 
may take only a month. It is difficult to detect any 
damage that is being done by inspecting the grain, 
as there is little difference between the injured and 
the uninjured grain. If, however, a quantity of the 
grain is placed in water the partly eaten grains float 
on the surface. 
The weevils cannot stand cold and on the approach 
of winter usually migrate to cracks or shelters in the 
floors and walls. In spring they return once more to 
any corn which they may find. C. granaria is unable 
to fly, but C. oryzae possesses flying wings. 
