6 CONTENTS. 



Protection of the bolls — Continued. p age . 



Proliferation from the wall of the boll 58 



Time required 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 



ILLUSTRATION'S 



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 



