DIV. INSECTS, 



U. S. DEPARTMENT OF AGRICULTURE, 



BUREAU OF ENTOMOLOGY— BULLETIN No. 83, Part I. 



L. O. HOWARD, Entomologist and Chief of Bureau. 



PRACTICAL INFORMATION ON THE SCOLYTID BEETLES 

 OF NORTH AMERICAN FORESTS. 



I. BARKBEETLES OF THE GENUS 

 DENDROCTONUS. 



BY 



A. D. HOPKINS, Ph. D., 



In Charge of Forest Insect Investigations. 



Issued October 11, 1909. 





WASHINGTON: 



GOVERNMENT PRINTING OFFICE. 



1909. 



