Technical Series, No. 17. 



U. S. DEPARTMENT OF AGRICULTURE, 



BTJREA.XJ OF EJNrTOlVtOLOG-Y. 



L O. HOWARD, Entomologist and Chief of Bureau. 



CONTEIBUTIONS TOWAED A MONOGEAPH 

 OF THE SCOLYTID BEETLES. 



I. THE GENUS DENDROCTONUS. 



By A. D. HOPKINS, Forest Entomc 



II. PRELIMINARY CLASSIFICATION OF THE SUFERFAMILY SCOLYTOIDEA. 



By A. D. HOPKINS, Forest Entomologist. 



WASHINGTON: 



<;ii\ i:i{NiMRNT PRINTING OFFICE. 

 1921. 



