THE MEXICAN COTTON-BOLL WEEVIL 269 



this, strict rules have been made against the shipment of 

 cotton seed or other materials that might carry the weevils. 



The boll weevil spreads chiefly by flying. This flight 

 and rapid spread occur during the fall months. In this 

 way, the weevil spreads into about fifty miles of new terri- 

 tory each season. It is expected to spread over the entire 

 cotton belt within a comparatively few years. 



How it passes the winter. The weevils which reach 

 maturity late in the fall are the ones that are most likely to 

 live through the winter. Fortunately, only from one to ten 

 weevils live through the winter out of every hundred that 

 attempt to do so. The weevils that mature in the late fall 

 find shelter in the old cotton bolls on the stalk, or under 

 any rubbish in or around the fields. The few that survive 

 the winter leave their places of shelter gradually during 

 a period of from ten to fourteen weeks, as a rule between 

 the last of March and the first of July. This gradual 

 coming out from winter quarters makes it very difficult to 

 do much to control the weevil early in the spring. 



Treatment for the weevil. This has proved to be a 

 very difficult insect to control. No poisons have proved 

 of much value in fighting it. It has been found that the 

 direct rays of the sun will destroy large numbers of the 

 insects while in the immature stages in the fallen squares, 

 when they are exposed to it. Some of our native ants, 

 which occur all through the cotton-growing area, are very 

 valuable helps, because they destroy large numbers of the 

 pest in its immature stages. A number of other insects 

 attack the immature insects in the squares and bolls and 

 destroy them. More than forty species of birds are known 



