31 



COLOR. 



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 rnle, 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 b}^ 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 larva3, the dark-brown 

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

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

 opment the scales are largely produced and give the strong yellow 

 tone to the color which is characteristic of them. 



The development of the scales appears to 'take place mostly after 

 the adult weevil has become quite dark in color but before it becomes 

 fully hardened. They seem, therefore, to be a sort of non-essential 

 aftergrowth which depends upon the surplus food supply remaining 

 after the development of the essential parts of the weevil structure. 



SIZE AND COLOR NOT INDICATIVE OF SEX. 



Eminent coleopterists have studied the boll weevil most carefully 

 with the purpose of discovering some external character by which the 

 sexes could be distinguished, but all have failed to find any reliable 

 points of distinction. The writer therefore does not hesitate to own 

 that he also has failed to find any reliable character for the distinc- 

 tion of the sexes. Many persons have the idea that the small dark 

 weevils are males and the larger and lighter-colored brownish-yellow 

 weevils are females. This idea is a mistaken one. In general it is 

 probably true that the males are slightly smaller than the females, 

 but judging from determinations of the sex of many hundreds of 

 weevils it may be stated positively that size and color are characters 

 which are related to food supply and length of the period of develop- 

 ment and are not indications of sex. The sexes seem to be about 

 equally represented among the smallest as well as the largest weevils. 



