42 THE MEXICAN COTTON-BOLL WEEVIL. 



young planted cotton having from four to eight leaves. At Victoria, 

 early in June, 1902, Mr. A. N. Caudell found, in examining 100 

 stubble plants growing in a planted field, that fully one-half of the 

 squares upon these plants were then infested. The planted cotton 

 was just beginning to form squares and was slightly injured at that 

 time. 



It appears, therefore, that stubble plants, where such exist, 

 receive a large part of the first attack of the hibernated weevils, 

 not because of any special attraction, but for the reason that they 

 are present long before the planted cotton has come up. The 

 occurrence of volunteer and stubble cotton in the fields in the early 

 spring is of considerable importance in the boll- weevil problem. 

 Tliroughout the coast regions, especially of southern Texas, stubble 

 cotton is very common in the fields, and there is hardly a region 

 of the South where volunteer cotton can not be found before the 

 normal planting is up. (See PI. VIII, a.) 



It is by no means certain that all or even a large proportion of 

 the hibernated weevils may be found upon the early plants, and this 

 renders their use as traps entirely impracticable. A number of 

 observations have shown that weevils frequently occur upon the 

 planted cotton, even when numbers of vigorous stubble plants may 

 be found within a comparatively short distance. In fact, at Victoria, 

 Tex., in 1904, many weevils were found feeding upon the planted 

 cotton for more than six weeks after the stubble plants were producing 

 fruit. 



DESTRUCTIVE POWER BY FEEDING. 1 



A glance at the figures in Table VIII is sufficient to show the 

 great destructive power of the Mexican cotton-boll weevil. It may 

 be seen that both in the field and in the laboratory the weevils of 

 the first generation are more active in making punctures than are 

 the hibernated weevils. These generations overlap too far to justify 

 us in attributing this difference to the influence of a higher temper- 

 ature alone, though this factor will account for a large part of it. 

 A comparison of the figures for males alone with those for females 

 alone or with those for males and females together shows that it is 

 very conservative to state that males make less than half as many 

 punctures as do females. By the habit of distributing their punc- 

 tures among a greater number of squares the destructiveness of 

 the females becomes at least five times as great as that of the males. 



This great capacity for destruction has been one of the most 

 evident points in the history of the spread of the weevil and has deeply 

 impressed the entomologists who first studied the insect in Texas. 

 In 1895 Mr. E. A. Schwarz, in writing of the work of the weevil at 

 Beeville, said : 



Each individual specimen possesses an enormous destructive power and is able to 

 destroy hundreds of squares, most of them by simply sticking its beak into them for 

 feeding purposes. 



ATTRACTIVENESS OF VARIOUS SUBSTANCES. 



Experiments have proved that the report which has sometimes been 

 circulated to the effect that cottonseed meal attracts the weevil is due 

 to mistaking other insects for it. Many tests, both in the laboratory 



1 Extracted from Bulletin 51, Bureau of Entomology, p. 61. 



