Technical Series, No. 20. 



U. S. DEPARTMENT OF AGRICULTURE, 



I3TJR,EA.XJ OF TOTTOMOJ^OGY. 



L. O. HOWARD. Entomologist and Chief o( Bureau. 



TECHNICAL PAPERS ON MISCELLANEOUS 

 FOREST INSECTS. 



CONTENTS AND INDEX. 



Issued February 12, 1921. 



WASHINGTON: 



GOVERNMENT PRINTING OFFICE. 



1921. 



