BEHAVIOR OF PAEASITTZED BUDS. 43 



regions, however, this requirement might be relaxed, and it is in such 



places that the injuries of the weevils are the greatest. 



BEHAVIOR OF PARASITIZED BUDS. 



SHEDDING OF WEEVIL-IXFESTED SQUARES. 



In a dry climate, like that of the Mexican plateau region, the drop- 

 ping of the squares in which the weevils have deposited eggs would 

 constitute a very effective adaptation. The weevil larva? do not sur- 

 vive a thorough drying out of the squares. It is only in the arid 

 districts of Mexico that the cotton plant has shown its ability to 

 escape from cultivation and maintain itself without human assistance. 

 if indeed it be not in some places a truly indigenous wild plant, as 

 several botanists have reported. But in a moist region like the cotton 

 belt of eastern Texas this habit of the plant has no practical use. 

 since as many of the weevils die when the injured squares remain 

 attached to the plant as when they fall to the ground. 



" It is generally True ThaT squares seriously injured by The weevil sooner or 

 later fall To the ground. Some plants, however, shed The injured squares more 

 readily Than do oThers. It seems To be a matTer of individual variation rather 

 Than a varietal character. Thus occasional plants retain a large proportion of 

 Their infesTed squares, which hang by the very Tip of The base of the sTem. 

 Normally The squares are shed because of the formation of an absciss layer 

 of corky Tissue across Their junction with The sTem. In The case of The squares 

 which remain hanging. The formation of this layer seems to be incomplete, or 

 else it becomes formed in an unusual plane, so that while The square is effecTu- 

 ally cut off, iT merely falls over and hangs by a bit of bark at its tip. In This 

 position iT dries thoroughly and becomes of a dark brown color. Plants 

 showing 6 or 8 of These dried brown squares are quiTe common in infesTed 

 fields. AlThough exposed to complete drying and the direct rays of the sun, 

 the larva? within are not all destroyed. * * * 



" IT seems a conservative estimate, therefore. To say ThaT fully one-Third of 

 These exposed dried squares may be expected to produce adults. Considering 

 the exposed condition of such squares This seems to be a very high pereent- 

 a g e * * * The observations made, however, certainly show That a complete 



a After the above had been written it was observed that the Pachon cotton 

 from western Guatemala, grown in an experimental plot at Lanham. Md.. has 

 the peculiar feature of a large calyx, which completely covers The young bud 

 and extends above it into long, slender, hairy tips. IT may be ThaT This is to be 

 looked upon as still another weevil-resisting adaptation. The weevils would be 

 able, undoubtedly, to bore through the calyx, but the hairy tips might hinder 

 their access to the bud. The bracts are much smaller and much more open 

 Than in the Kekchi and Rabinal varieties, but The lacinia 1 . or teeth, along Their 

 margins are raTher stiff and are clothed with numerous hairs, stronger and 

 more brisTlelike Than in the Kekchi and Rabinal varieties, and able to keep The 

 lacinia^ from closing together. It may be that the greater rigidity of the lacinia? 

 and the bristles gives better protection than the open position of the bracts 

 would indicate. The case is in reality quire different from That of the Sea 

 Island varieties, where the bracts are both naked and open. 



