Technical Series, No. 17, Part I. 



U. S. DEPARTMENT OF AGRICULTURE, 



L. 0. HOWARD, Entomologist and Chief of Bureau. 



CONTKIBUTIOXS TOWAPJ) A MONOGllAPH OF 

 THE SCOLYTIl) BEETLES. 



I. THE GENUS DENDROCTONUS. 



A. D. HOPKINS, Ph. D., 



In Charge of Forest Insect Investigations. 



Issued June 30, 1909. 



WASHINGTON: 



GOVERNMENT PRINTING OFFICE. 



1909. 



