CONTENTS. 11 



Hibernation — Continued. Page. 

 Survival of hibernated weevils — Continued. 



Relation of shelter to survival 112 



Relation of climate to survival 112 



Longevity of hibernated weevils 114 



Maximum length of life 115 



Relation of emergence and longevity to time of planting 116 



Nature of weevil activity following emergence from hibernation 116 



Natural control 118 



Climatic control 120 



Climatic influences on vitality and activities 121 



Field observations on mortality due to heat and dryness 122 



General discussion of the relations of temperature to the boll weevil. . 125 



Upper zone of fatal temperature 126 



Zone of aestivation 127 



Zone of activity 127 



Zone of hibernation 127 



Lower zone of fatal temperatures 128 



Fatal variations of temperature 129 



Effects of flooding upon the weevil 131 



Plant control 132 



Proliferation 132 



Other phases of plant control 135 



Diseases 136 



Parasitic and predatory insect enemies 136 



A brief summary of the insect species attacking the boll weevil 136 



Birds 145 



Repression 147 



Effect of burial of squares and weevils 147 



Laboratory experiments in burial 148 



Burial of adult weevils at time of hibernation 148 



Conclusions from burial experiments 148 



Insecticides 149 



Powdered arsenate of lead 150 



Machines 151 



Field machinery 151 



Ginning machinery 152 



Futile methods which have been suggested 153 



Mineral paint and cottonseed oil 153 



Spraying 153 



Sulphur 153 



Paris green 154 



Trapping at light 154 



Other proposed remedies 154 



Requirements of a satisfactory method of boll-weevil control 155 



Basis for means of repression 155 



Summary of means of repression of the boll weevil 160 



Destroying the boll weevil in cotton seed 162 



Legal restrictions regarding the boll weevil 164 



United States Statute 164 



Quarantines of the several States 164 



Bibliography 169 



Index 176 



