CONTENTS, 



Page. 



Introduction 7 



Selective inflnence of the boll weevil 10 



General protective characters H 



Dwarf habit and determinate growth of Kekchi cotton 11 



Variations in the Kekchi cotton I5 



Effects of Guatemalan conditions on United States varieties. 17 



Acclimatization of Kekchi cotton in the United States 17 



Early bearing facilitated by long basal branches 19 



Early rejection of superfluous squares 20 



Seasonal bearing of perennial varieties 23 



Annual cutting back of perennial varieties 24 



Hairy stalks and leaf stems 25 



Pendent bolls 27 



Extrafloral nectaries 28 



Nectaries of the leaves 30 



External nectaries of the involucre _ 31 



Inner nectaries of the involucre 31 



Nectaries of Guatemalan Sea Island cotton 32 



Continued secretion of nectar 32 



Bractlets subtending inner nectaries 33 



Efficiency of the kelep protection , 34 



Other nectar-bearing plants visited by the keleps 36 



The in vohicre as a protective structure _ . . * _ . . 37 



Involucral bracts grown together * 37 



Appressed margins of bracts 38 



Large involucres of Kekchi cotton ,, 39 



Opening, or flaring, of bracts avoided 40 



Hairy margins of involucral bracts . 41 



Extent of protection by involucre 41 



Advantage of open involucres 42 



Behavior of parasitized l)uds 43 



Shedding of weevil-infested squares ... 43 



Countings of fliired and fallen squares 45 



Prolif, ration of internal tissues of buds 46 



Causes and conditions of bud proliferation .' 49 



Proliferation in other varieties 50 



Protection of the bolls . . .51 



Persistence of flowers , .51 



Immunity of very young bolls 52 



Rapid growth of young bolls _ 55 



Thick- walled bolls ,56 



Tough linings of chambers of bolls - . 56 



5 



