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SPECIAL DEVICES FOR DESTROYING WEEVILS. 
The impression is more or less general that the only important way 
in which weevils may be killed is by the removal of the infested 
plants and that all other steps in the system of control are merely to 
avoid damage by the weevils that have survived that destruction, and 
their offspring. In spite of this impression, however, it is urged that 
the destruction of myriads of weevils can be accomplished during the 
growing season. This is to be done by working in cooperation with 
the natural agencies that destroy the weevil. 
In making examinations of many thousands of infested squares 
from different localities and different situations in cotton fields it 
was found that mortality was conspicuously greatest where the sun- 
light was least obstructed and the heat, consequently, the greatest. 
The mortality in infested squares in the middles was many times 
Fic. 6.—Chain cultivator, side view. (Original.) 
as great as in the case of squares which remained under the shade of 
the branches. The temperature at the surface of the ground during 
warm days runs considerably higher than at a few feet above the sur- 
face. For instance, it was found that when the temperature was 
100° F. in the regular Weather Bureau shelter about 4 feet above the 
ground the thermometer registered 140° F. on the surface. Likewise 
90° F. in the shelter was accompanied by 120° F. on the ground and 
85° F. in the shelter by 110° F. on the ground. It is not surprising, 
therefore, that the cotton squares that fall to the ground and are not 
shaded are very quickly baked, so that the weevils perish—if not 
from heat, then from the hardening of the food supply. In most 
vases they are simply roasted, their bodies assuming the appearance 
of larvee that have been placed in a flame. 
Chain cultivator— When the foregoing facts came to light efforts 
were made to perfect a device that would bring the infested squares 
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