96 



activity may seem slight to account for the evident selection of the 

 smoother varieties, no greater difference could be found. As is shown 

 by Table XI, on page 46, the selection is not due to a difference in taste 

 of the squares. 



In order to test the resistance which varying degrees of pilosity 

 might offer to weevil progress, a number of experiments were made 

 with various stems or fruits. In climbing upon the stems of King 

 plants weevils would catch the spines with the forefeet while pushing 

 themselves upward by means of the tibial spurs of the hind legs 

 placed against the epidermis and between the spines. It was evident 

 that their progress was considerably^ hindered, and several attempts 

 were often made before a firm foothold was secured. 



Okra i^ods were next tried, as upon them the spines are very short 

 and stiff. Weevils climbed these pods with little difficulty. 



The seed pods of Sunset Hibiscus were also tested. The spines 

 upon these are from 2 to 3 millimeters long; they stand thickly and 

 are quite stiff. Over these spines weevils walked easily, but though 

 they attempted vigorously to get their heads down between the spines 

 far enough to feed, they were unable to do so. A number of weevils 

 were kept for several daj^s upon these pods, but they were unable to 

 feed. . The spines were then removed from a small area, and the 

 insects began to feed immediately. 



Weevils travel with difficulty over loose cotton fibers, as their feet 

 become entangled among them. 



DESTRUCTION OF LARV^ AND PUP^ IN BOLLS AND SQUARES BY 

 ABNORMAL PLANT GROWTH. 



In making examination of several thousands of infested squares a 

 small j)ercentage was found in which the larvae had evidently been 

 killed by an abnormal condition of the interior, which may be char- 

 acterized as a process of gelatinization. This change begins at the 

 point of injury and spreads. Instead of the normal growth of the 

 anthers there takes place a change which appears to be something like 

 the swelling of starch granules. The interior becomes soft and pulpy, 

 and by the swelling considerable internal pressure is produced. The 

 death of the larva3 results either from unfavorable food conditions or 

 from the internal pressure, which in many cases is sufficient to distort 

 the square. Whether from these or other causes, from 10 to 20 per 

 cent of the larvse usually die within the squares. 



Gelatinization sometimes occurs in small bolls, but more rarely as 

 bolls become larger and more mature. In large bolls in which seeds 

 are nearly matured the feeding of the weevil larvfe often causes seeds 

 to sprout, and in several such cases pupae have been found crushed 

 by the rapid growth of the caulicle. 



In examining nearly 1,000 bolls, taken partly from King and partly 

 from native cotton, it Avas found that in the early maturing King the 



