THE GRAIN BUG. DBA 
and around the bases of large uncut tufts of native grasses. The luxu- 
riant growth of dead Russian thistle along irrigation ditch banks, 
fence rows, and roadsides, as well as piles of débris in the fields or pas- 
tures, affords ideal hibernating quarters for the insect. In cleaning 
out any of these habitats during the spring, it is not unusual to find 
scores of the adults concentrated within a very limited space. This 
circumstance at once suggests a simple and effective method for con- 
trolling the pest. 
The hibernating adults apparently lack the power to burrow be- 
neath the surface of the soil. Generally they are found directly 
underneath the material composing their hibernating quarters or in 
loose material on the surface of the ground. 
MORTALITY DURING HIBERNATION. 
In some localities there is a high percentage of adult: mortality 
during hibernation. Frequently in the spring large numbers of dead 
individuals are found grouped together with only a very few living 
forms remaining. Under these circumstances it is probable that the 
hibernating quarters were exposed to unusually severe conditions and 
did not afford the contemplated protection from winter temperatures. 
It is also possible that parasites, predators, or fungous diseases oc- 
casionally may be responsible for the high rate of mortality. 
Under more favorable conditions for hibernation it is not uncom- 
mon to find that among hundreds of adults at least 95 per cent have 
survived the winter. 
Severe winters undoubtedly result in the death of a large per- 
centage of hibernating adults and form one of the most important 
factors in restricting destructive outbreaks of the species. 
CHANGE OF COLOR DURING HIBERNATION. 
In hibernation the adults of Chlorochroa sayi change to a green- 
ish-pink color, quite distinct from their normal summer appearance. 
This change is not evident in the autumn when the adults are seeking 
their winter quarters or in the spring directly after they have 
emerged from hibernation. Adults collected in the autumn and kept 
active throughout the winter in a stove-heated room assumed the 
same characteristic color as the inactive adults in outdoor hibernating 
quarters. The specimens reverted to their normal coloration in the 
spring. Possibly this change in the appearance of the species during 
the summer and winter seasons may serve as protective coloration. 
The winter coloration persists in the pinned museum specimens of 
adults collected from hibernation. 
