RAPTD GROWTH OF YOUNG BOLLS. 55 



cotton flowers and well dusted over with pollen suggests the possi- 

 bility that in this district at least they were a not unimportant 

 agency of cross-fertilization. The performance of such a service by 

 the boll weevil would be comparable to the famous case of the yucca 

 and its moth, the plant being dependent for cross-fertilization upon 

 its insect parasite. The weevils eat the pollen from the bud ; that 

 they visit the flowers for the same purpose seems highly probable. 

 The investigations of Messrs. Hunter and Hinds have shown, indeed, 

 that a pollen diet is a necessity for the complete sexual maturity and 

 reproduction of the weevils; if without buds to feed upon they 

 seldom copulated and never laid eggs. 



RAPID GROW T TH OF YOUNG BOLLS. 



Mr. John H. Kinsler, who gave careful attention to the earlier 

 stages of the Guatemalan experiment, gained an impression that the 

 young bolls of the Kekchi cotton increased in size with a rapidity 

 distinctly greater than that of the United States Upland varieties 

 planted alongside, It was not practicable to establish the fact by 

 carrying out a series of daily measurements, though it was possible 

 to ascertain from dated tags used in connection with the hybridiza- 

 tion experiments that the Kekchi cotton can grow bolls to full 

 size in less than a month from the time the flower opens. Plate IX, 

 figure 2, shows on the right tw T o bolls of Kekchi cotton less than a 

 month from flowering. On the left are the two largest bolls from an 

 adjoining plant of King, the seed of both varieties having been sown 

 the same day. 



Such an acceleration of the growth would be of very obvious utility 

 in lessening the period in which the danger of infestation is greatest, 

 A large proportion of the weevils found in adult bolls of Kekchi cot- 

 ton Avere in " locks " or compartments of diminutive size, showing 

 that the infestation had taken place while the boll was less than half 

 grown. Indeed, the weevils seldom seem to be able to affect lodg- 

 ment in bolls more than half grown, although numerous attempts 

 are made in fields where the weevils are numerous. The following 

 field note describes such an instance : 



A boll showing many external marks of weevil punctures was found on being 

 cut up with care to have been attacked at least fourteen times. In five cases 

 the outer wall seemed not to have been penetrated, but in nine others there had 

 been complete perforations. All of these had been closed, however, -by prolifer- 

 ation from the inner surface, and no living larvae were found. 



Such persistent attacks, however, may finally induce a diseased 

 condition which interferes with the normal growth of the boll, even 



"Hunter, W. D., and Hinds. W. E., 1905. The Mexican Cotton Boll Weevil, 

 Bui. 51, Bureau of Entomology, U. S. Department of Agriculture, p. 113. 



