30 



darkeniiit:: of the <j;i-oiiud color makes the scales more apparent, and 

 thus .i^ives the impression of further develoi^ment after emergence has 

 taken place. 



SIZE OF WEEVILS. 



Size of boll weevils is an especially variable quantity, and, as usual, 

 varies almost directly in proportion to the abundance of the larval 

 food supj)ly and the length of the i)eriod of larval development. The 

 extremes are so great that the smallest and largest weevils would be 

 thought by one not thoroughly familiar with them to be of entirely 

 different species. So far as dimensions may convey an idea of the 

 size, we may say that the weevils range from 3 to 8 mm. {} to ^ inch) 

 in length, including the j)roboscis extended, and from 1 to 3 mm. (oV 

 to ^ inch) in breadth at the middle of the body. (See PI. I, fig. 1.) 



RELATION OF SIZE TO FOOD SUPPLY. 



The smallest weevils are developed from sqviares Avhich were very 

 small, and wliich, for some reason, either of i^lant condition or of 

 additional weevil injurj% fell very soon after the egg was deposited. 

 The supi)ly of food was not only small, but, owing to the immaturity 

 of the iiollen sacs, its quality was also poor. Normally squares con- 

 tinue to grow for a week or more after eggs are deposited in them, and 

 such squares produce the weevils of average size and color. 



The largest weevils are produced in bolls which grow to maturity. 

 In them the food supply is most abundant, and the period of larval 

 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 made upon the weight of adults. 



WEIGHT OF ADULTS. 



The weevils used in these experiments were bred to insure their 

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

 some time to bring them up to their normal weight. 



Table V. — Suinmarij of tceiglit of iveevils. 



Source of weevils. Number. 1'?^^^^^® 



Grain. 



Brofl from picked small squares 25 0.105 



Bred from average fallen squares 68 .231 



Bred from large bolls - , 



Total - - 



Average weight per weevil, all sources 



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

 weight of the extremes in size, but they do indicate the difference in 

 the average weevil of each class. 



