6 CONTENTS. 



Protection of the bolls — Continued. Page. 



Proliferation from the wall of the boll _ 58 



Time reqnired for proliferation 60 



Efficiency of adaptive characters of bolls 61 



Bacterial diseases following weevil injuries 62 



Breeding in buds a derived habit 62 



Relation between proliferation in buds and in bolls . 64 



Protection of seeds by lint 65 



Protective seed arrangement in Kidney cotton 66 



Cultural value of Kidney cotton . 67 



The nature and causes of adaptations . 67 



Conscious and unconscious selection 70 



Summary of adaptations 72 



Classification of adaptations . 72 



Adaptive characters of different types of cotton 73 



Concluding remarks . 74 



Description of plates .._ 78 



Index 79 



ILLUSTRATIONS 



Plate I. Valley at Secanquim, Alta Vera Paz, Guatemala, the scene of 



experiments with weevil-resisting cotton Frontispiece. 



II. Fig. 1. — Mature plant of Kekchi cotton. Fig. 2. — Kekchi cotton 



plant with bolls 78 



III. Involucres of Kekchi cotton, showing nectaries and bractlets 78 



IV. Fig. 1.— Involucres of Rabinal cotton, showing connate and ap- 



, pressed margins. Fig. 2. — Open involucres of Egyptian cotton _ 78 

 V. Fig. 1. — Young buds of Kekchi cotton with weevil punctures. 



Fig. 2. — Buds of Kekchi cotton with proliferation 78 



VI. Large buds of Kekchi cotton with proliferation 78 



VII. Weevil-infested bolls of Kekchi cotton 78 



VIII. Carpels of Kekchi cotton, showing proliferation 78 



IX. Fig. 1.— Kekchi cotton, successive stages of the boll. Fig. 2. — 



Kekchi cotton bolls (right) compared with King bolls (left)... 78 

 X. Fig. 1.— Rabinal cotton with bolls. Fig. 2. — Bolls and seeds of 



Kidney cotton 78 



