U. S. D. A., B. E. Bui. 85, Part V. C. F. 1. 1., June 15, 1910. 



PAPERS ON CEREAL AND FORAGE INSECTS. 



THE NEW MEXICO RANGE CATERPILLAR. 



(Hemileuca olivix Ckll.) 



By C. N. Ainslie, 

 Agent and Expert. 



INTRODUCTION. 



During the month of August, 1908, information reached the United 

 States Department of Agriculture at Washington that a destructive 

 invasion of certain sections of the cattle range in northeastern New 

 Mexico by an immense army of caterpillars had been in progress for 

 several years, and that the damage seemed to be steadily increasing 

 with each successive year. 



The facts, as stated, were so specific and the source so trustworthy 

 that the matter was deemed worthy of immediate attention. Ac- 

 cordingly the writer, who was then busy with other insect problems 

 in southern New Mexico, was instructed to proceed as soon as prac- 

 ticable to the infested territory in the vicinity of Springer, N. Mex., 

 make a thorough study of existing conditions, and report on the life 

 history of the pest and the feasibility of methods of extermination 

 or control. 



The following pages give the results of this investigation which 

 was begun in October, 1908, and was continued throughout the 

 greater part of the summer of 1909. 



The writer is under great obligations to Prof. F. M. Webster, to 

 whose advice and cooperation many of the results of the study are 

 due; to Dr. Harrison G. Dyar, who has kindly described the various 

 larval stages and the adults and has supervised the drawings of the 

 larval and adult forms, besides contributing the entire section relat- 

 ing to "the specific identity of the insect concerned;" to Messrs. 

 Frank and Charles Springer and to Mr. Henry Springer for the many 

 kindly courtesies that have made this investigation possible; to Mr. 

 H. M. Letts, of Koehler, N. Mex., for valuable assistance ; and to others 

 both in New Mexico and in Washington who have in various ways 

 aided in this study. The writer is responsible for the statements 

 concerning the life history of the insect herein recorded, all of which 

 are original with the present investigation and are believed by him 

 to have been correctly interpreted and recorded. 



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