42 



development is several times as long as it is in squares. Possibly 

 these differences in size may be better shown by a summary of 

 observations which were madjB upon the weight of adults. 



WEIGHT OF ADULTS. 



The weevils used in these experiments were bred to insure their 

 coming from the proper source. After emergence they were fed for 

 some time to bring them up to their normal weight. 



Table VII. — Summary of weight of weevils. 



Source of weevils. Number. ^jjJSjJJJ? 



Grain. 



Bred from picked small squares ! 25 ! 0. 105 



Bred from average fallen squares I 68 I .'231 



Bred from large bolls i 69 .268 



Total | 162 



Average weight per weevil, all sources ! 



36. 825 

 .227 



It should be noted that these figures do not nearly represent the 

 weight of the extremes in size, but the} T do indicate the difference in 

 the average weevil of each class. 



ccvlok. 



Color is very often a variable character in insects, and the boll 

 weevil presents considerable range in this respect. Whatever influ- 

 ences the size of the larva affects directly the size of the adult, and it 

 is noticeable that weevils of the same size are also, as a rule, closely 

 alike in color. In general, the smaller the size of the weevil the 

 darker brown is its color; the largest weevils are light yellowish 

 brown. Between these two extremes are the majority of average- 

 sized weevils, which are either of a gray-brown or dark yellow-brown 

 color. Weevils developing in large bolls, having an abundant food 

 supply and a developmental period averaging more than twice that 

 of weevils in squares, are larger in size and more yellowish in color 

 than are those from squares. 



The principal reason for the variation in color lies in the degree of 

 development of the minute hair-like scales, which are much more 

 prominently developed in the large than in the small specimens, 

 although the color of old specimens is often changed by the rubbing 

 off of the scales. The scales are yellow in color, while the ground 

 color of the chitin bearing them is a dark brown or reddish brown. 

 When the scales are but slightly developed, as seems to be the case 

 with small weevils produced from underfed larva?, the dark-brown 

 ground color is predominant, while in the case of large weevils pro- 

 duced from larva? having abundant food and a long period of devel- 



