402 SOUTHERN FIELD CROPS 



370. Spread of the boll-weevil. — Ordinarily the adult 

 weevil flies but a few rods at a time. However, when food 

 becomes scarce in the fall, distances of as much as fifty 

 miles are traversed in a few days. This fall migration, ap- 

 parently in search of food, explains the rapid spread of 

 the boll- weevil. The weevil usually advances about fifty 

 miles a year. However, in 1909 its 'eastward spread across 



Fig. 177. — The Hinds Chain Cultivator foe Tillage and for 



DRAWING THE FALLEN SQUARES TO THE WaTER-FURROW. 



the southern part of Mississippi was more than twice this 

 distance, bringing the weevil at the end of 1909 to within 

 about ten miles of the Alabama Une in the vicinity of Mo- 

 bile. In the fall of 1910 this insect invaded several coun- 

 ties in the southeastern part of Alabama. Probably its 

 extension northward will be somewhat less rapid than its 

 eastward spread. 



Crossing the Rio Grande from Mexico about 1892 it 

 has persistently spread eastward and northward. The 

 map (Fig. 178) shows that by the close of 1909 the boll- 

 weevil occupied the greater part of the cotton-growing 



