BROAD-NOSED GRAIN WEEVIL. | 3) 
LIFE HISTORY (PI. 1).? 
The adults of the broad-nosed grain weevil possess functional 
| wings, and although not great fliers they are capable of making short 
| flights in search of food. They fly to the cornfields in the summer, 
feed on the grain, and deposit eggs in it before it becomes fully 
hardened. 
The damaged and exposed ears of corn are the ones that are 
attacked by the weevils, those ears that have a well-developed and 
tightly fitting shuck being entirely immune from attack. 
After the grain is harvested and placed in storage the work of 
destruction continues. The kernels infested in the field are com- 
pletely destroyed, and the multiplying weevils attack cracked and 
broken kernels and grain that is softened by excess moisture or is 
damaged by the depredations of other grain pests. 
OVIPOSITION. 
- Under favorable conditions oviposition occurs more frequently dur- 
ing the hours of the morning; eggs are laid, however, at all times of 
the day. 
The female weevil excavates the egg cavity In a manner very 
similar to that of Sitophilus oryza. ‘The weevil places herself in the 
desired position. The sharp hook or claw on the end of the tibia of 
each leg is dug into the surface of the kernel, the four legs thus form- 
ing pivots on which the body oscillates. This oscillating movement 
of the body, together with a turning movement of the head, imparts 
to the proboscis a combined up-and-down and rotary motion. The 
position of the legs is not changed, as a rule, until the excavation is 
completed, and the proboscis or beak is seldom withdrawn during 
this time. Work on the cavity continues until its depth approxi- 
mates the length of the beak from the tip to the eyes. The sides are 
then smoothed off. 
After the completion of the cavity the weevil reverses her position 
and places the tip of her abdomen over the mouth of the egg cavity. 
After a period of from two to three minutes the egg is ejected from | 
the ovipositor into the cavity, followed by a liquid secretion that 
forms a cap and cements the egg into place. This secretion quickly 
hardens. Immediately after the egg is deposited the weevil turns 
about and tamps down the edges of the egg cap with her beak, 
picking up small pieces of the borings from the excavation and tamp- 
ing in around the edges. 
The egg cap is transparent, and the outer surface is invariably 
exactly level with the surrounding surface of the corn. After the 
young larva has emerged from the egg and the egg cavity is filled 
with larval borings it is often difficult to detect the original position 
of the egg. 
?In breeding experiments from which the life-history data were taken corn was used as the host Seed. 
