UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 358 km 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



s&Jr'&j-u 



Washington, D. C. 



PROFESSIONAL PAPER 



April 12, 1916 



STUDIES OF THE MEXICAN COTTON BOLL WEEVIL 

 IN THE MISSISSIPPI VALLEY. 



By R, AY. Howe. 

 Entomological Assistant. Southern Field Crop Insect Investigations. 



CONTENTS. 



Page. 



Introduction 1 



Longevity of adult weevils 3 



Food plants of the weevil 8 



Feeding habits on cotton leaves and terminals. 11 



Sex of adults 12 



Feriod from emergence to oviposition 12 



Period from first feeding on squares to ovipo- 

 sition 13 



Fecundity 13 



Oviposition period 23 



Page. 



Rate of oviposition 24 



Maximum number of eggs per day 24 



Period from deposition of last egg to death... 24 

 Activity of females in different parts of the 



day 25 



Cessation of oviposition by hibernated weevils . 26 



Total developmental period 26 



Effect of size of square on weevil development. 30 



Generations 30 



Summary 31 



INTRODUCTION. 



Shortly after 1892, when the Mexican cotton-boll weevil (Antho- 

 nomus grandis Boh.) invaded Texas on its northward and eastward 

 journey and its extreme importance was seen, complete data were 

 secured on the various biological functions. In recent years, how- 

 ever, numerous observations have shown that, under new climatic 

 and other environmental conditions to which the weevil has been 

 subjected in its spread, changes have been taking place in many of 

 these functions. In addition, a new variety of the boll weevil has 

 been found breeding in a wild cotton (TJiurberia tliespesioides) occur- 

 ring in the mountain ranges of southeastern Arizona, and this weevil 

 (which has been described as Antlionomus grandis tliurberiae Pierce) 

 has been found to possess habits which differ in many vcnjs from 

 those of its near relative on cultivated cotton. Consequently, it has 

 been necessary to repeat many studies under both the old and the 

 new conditions and to include the new variety. In this way the 



Note.— This bulletin is of interest to entomologists in the cotton belt. 

 23922°— Bull. 358—16 1 



