UNITED STATES DEPARTMENT OF AGRICULTURE 



,„ BULLETIN No. 358 i 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



jru^^\JV 



Washington, D. C. 



PROFESSIONAL PAPER 



April 12, 1916 



STUDIES OF THE MEXICAN COTTON BOLL WEEVIL 

 IN THE MISSISSIPPI VALLEY. 



By R. W. Howe. 

 Entomological Assistant. Southern. Field Crop Insect Investiyations. 



CONTENTS. 



Page. 



Introduction 1 



Longevity of adult weevils ' 3 



Food plants of the vs'eevil 8 



Feeding habits on cotton leaves and terminals. 11 



Sex of adults 12 



Period from emergence to oviposition 12 



Period from rflrst feeding on squares to ovipo- 

 sition 13 



Fecimditj'- 13 



O viposition period 23 



Kate 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-holl weevil {Antlio- 

 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 (Tliurheria thespesioides) occur- 

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

 (which has been described as Anthonomus grandis thurheriae Pierce) 

 has been found to possess habits which differ in many ways 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 conditi'ons and to include the new variety. In this way the 



KoTE.— This biillelin is of interest to entomologists in the cotton belt. 

 23922°— Bull. 358—16 1 



