BEOAD-NOSED GRAIN WEEVIL. 



LARVAL HABITS. 



The larva or grub bores straight down into the grain at first and 

 is rarely found near the surface. It tunnels around rather aimlessly, 

 filling up the passageway behind it with frass and borings. It 

 usuall}^ remains in the soft parts of the grain. 



PREPUPAL STAGE. 



When fully grown the larva prepares for the change to the pupa 

 or resting stage. It uses the end of its burrow for a pupal chamber, 

 packing the frass and borings at the ends into a compact mass. 



The larva lengthens out and becomes sluggish, assuming the pre- 

 pupal form. This stage lasts for one day in warm weather and two 

 days in winter. 



PUPAL STAGE. 



The pupal stage lasts for a period of five days during warm weather 

 when the temperature ranges from 65° to 99° F., with a mean of 

 about 81°. As with the other stages, cold weather has the effect of 

 lengthening the period. Table 3 contains data showing the varying 

 length of this stage at different times of the year. 



NUMBER OF MALES AND FEMALES. 



Of several hundred weevils reared in the laboratory and of large 

 numbers collected in the field, the males and females were about 

 equal in numbers. The males and females closely resemble each other 

 in outward appearance and can not be differentiated without the 

 aid of a magnifying glass. 



As with many other weevils the beak of the female differs slightly 

 from that of the male and affords a ready means of distinguishing 

 between the two sexes. The beak or proboscis of the female is approx- 

 imately equal in width for its entire length and is longer and more 

 slender than that of the male. The beak of the male is slightly 

 enlarged at the tip and narrows gradually toward the base. 



COPULATION. 



Copulation occurs within a few days after emergence and is re- 

 peated at intervals. It occurs chiefly at night. These weevils are 

 rarely to be seen in copula during the day. 



Unfertilized females have been observed to lay eggs but rarely. 

 None of these eggs have been found to hatch, so it is doubtful 

 whether unfertilized females are capable of laying fertile eggs. 



. LIFE CYCLE. 



The period from egg to adult during warm weather averages about 

 30 days, which with an average preoviposition period of 22 daj^s gives 



