UNITED STATES DEPARTMENT OF AGRICULTURE 



1 BULLETIN No. 344 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief. 



Washington, D. C. PROFESSIONAL PAPER. January 18, 1916 



STUDIES ON THE BIOLOGY OF THE ARIZONA WILD 

 COTTON WEEVIL. 1 



By B. B. Coad, 

 Entomological Assistant, Southern Field Crop Insect Investigations. 



CONTENTS. 



Page. 

 Introduction 1 



Distribution of the Thurberia plant and 

 weevil 2 



Habitat of plant and weevil 3 



Seasonal activity of plant and weevil in nature 6 



Emergence of weevils 8 



.Relative attraction of cotton and Thurberia 



for weevils 10 



Life-history studies 13 



Parasites and predatory enemies of the weevil . 23 



INTRODUCTION. 



Early in 1913 it was announced by Mr. O. F. Cook of the Depart- 

 ment of Agriculture that a weevil, apparently identical with the 

 Mexican cotton boll weevil (AntTionomus grandis Boh.), had been 

 found breeding in the fruit of a wild cotton plant ( Thurberia tliespe- 

 sioides) in the mountains of southeastern Arizona. 2 This announce- 

 ment was at once followed by explorations in Arizona to determine 

 the distribution of the weevil and its host plant, and research work on 

 the habits, life history, and economic importance of the species. 

 Specimens were sent to the writer at Victoria, Tex., during the 

 summer of 1913, and there as many as possible of their life functions 

 were tested in comparison with the native weevils. Taxonomic 

 study of the Texas and Arizona weevils showed the latter to be a 

 distinct variety, and it was described by Mr. W. Dwight Pierce as 

 Anihonomus grandis tJiurberise. 3 The biological investigations showed 



1 Anthonomus grandis thurberiae Pierce. 



2 Cook, O . F. A wild host plant of the boll weevil in Arizona. In Science, n. s., v. 27, no. 946, p. 259- 

 261, Feb., 1913. 



s Pierce, W. D. The occurrence of a cotton boll weevil in Arizona. In U. S. Dept. Agr., Jour. Agr. 

 Research, v. 1, no. 2, p. 89-96, Nov. 10, 1913. 



Note.— The investigations on which this paper is based were conducted under the direction of W. D. 

 Hunter, in charge of Southern Field Crop Insect Investigations. 

 14889°— Bull. 344—16 1 



