14 
BULLETIN 1393, U. S. DEPARTMENT OF AGRICULTURE 
the rest. Dorsal area of each armed with a pair of large spines and a pair of 
smaller ones. Lateral area of each tergite hearing a spine, at hase of which is 
a small seta. Epipleural Lobes each obscurely armed with two minute setae. 
Ninth segment armed as usual with two prominent pleural spines. 
LIFE HISTORY AND HABITS 
The granary weevil normally hibernates during the winter in 
either the adult or the larval form. The adult is resistant to low 
temperatures and will survive a very cold winter. Adults resume 
activity with the first warm weather of spring, and egg haying soon 
begins. Overwintering larvae at that time begin pupating. Hiber- 
nating adults kept in the laboratory at Washington, D. C, resumed 
egg laying in the early part of March. 
THE ADULT 
After transformation from the pupal 
to the adult form, the weevil remains 
within the seed for a short time until 
the body integuments harden and the 
color has changed to a dark chestnut 
brown. Some weevils remain to feed 
for a considerable time within the 
larger seeds. Shortly after emergence 
copulation takes place and is repeated 
at frequent intervals throughout the 
life of the weevil. 
The weevils are rather sluggish in 
their actions and are very easily 
handled. If disturbed in any way 
they draw their legs up close to the 
body and remain motionless for some 
time. The females may be distin- 
guished from the males by their 
smoother and more slender beaks. 
PARTHENOGENESIS 
Fig. 8.— The granary weevil: Pupa, ventral 
view. Enlarged about 37 times 
Virgin females of the granary weevil 
have been observed to deposit an oc- 
casional egg, but none of these hatched. 
DURATION OF ADULT LIFE WITHOUT FOOD 
The granary weevil is capable of surviving without food for a 
considerable period, much longer than the closely related rice weevil, 
possibly because of its less active life and its restriction to a more 
temperate climate. The temperatures at which the insects were kept 
under observation had a very marked effect on their powers of resist- 
ance to starvation. Five lots of 50 weevils each were kept without 
food until they died. Each lot was placed in a separate compart- 
ment held at a constant temperature. These temperatures ranged 
from 55° to 85° F. and were maintained with but slight variation 
for the entire period and at a rather high humidity. The results are 
given in Table 1. 
