95 



transportation of the pests from one locality to another was most 

 evident. 



A casual examination of the dirt separators which are now in use 

 in the more modern ginneries shows that immense numbers of weevils 

 brought in from the fields are separated from the lint by these devices. 

 Even where these separators are used, however, a short search in the 

 seed house will show that many weevils pass through alive. A single 

 hour's search in the seed house of a first-class ginnery, where dirt 

 separators are in use, yielded seven boll weevils in perfect condition, 

 and a number of other and much larger insects. In addition to these 

 a number of fairly large spiders, most of which were in perfect condi- 

 tion, were also found. Numerous pupae may pass through the gins 

 unharmed in the cells formed by the larvae. These cells are similar, 

 both in size and shape, to the seed, and may often be mistaken there- 

 for (PL XL, fig. 44). Distribution of weevils in seed is therefore 

 easily possible, and uninfested localities should guard carefully 

 against importing weevils in this way. 



The most valuable suggestion for reducing the important effect 

 that gins have in spreading the weevil is in the improvement of the 

 cleaning devices referred to above, and in encouraging their more 

 general use. A particular study of this matter will be made during 

 the season of 1904. 



NATURAL CONTROL. 



Doubtless many factors are concerned in the natural control of the 

 boll weevil. The most important ones are probably included among 

 the following topics: 



MECHANICAL CONTROL. 



PILOSE OBSTACLES TO WEEVIL PROGRESS. 



In testing the susceptibility of various cottons to weevil injury it 

 was found that the variety of Egyptian cotton grown (Mit Afifi) was 

 more severely injured than was any other. The next in order were 

 Sea Island and Cuban tree cotton, while the American cottons, repre- 

 sented especially by King's Improved, were less severely injured than 

 were any of the others. It may be noted that the three varieties first 

 mentioned seem more closely related to each other than any of them 

 do to the American. The reason for the evident choice of these cot- 

 tons was carefully sought for, but the only difference which seemed 

 worthy of consideration was found in the varying degree of pilosity 

 upon the stems (PL XIII, fig. 50). It was found that Egyptian stems 

 were almost perfectly smooth, while Sea Island and Cuban resembled 

 it closely in that respect. Many American cottons, and King's 

 Improved especially, are quite pilose, and it was often noted that upon 

 these weevils showed some slight difficulty in moving about or in 

 climbing the pilose stems of the plant. While this obstacle to weevil 



