SPECIAL BULLETIN./ 



HATCH EXPERIMENT STATION 



OF THE 



MASSACHUSETTS AGRICULTURAL COLLEGE. 



THE PTEROPHORIDy 



OF NORTH AMERICA. 



C. H. FERNALD, A.M., PH.D. 



REVISED EDITION. 



July 30, 1898. 



BOSTON : 



WRIGHT & POTTER PRINTING CO., STATE PRINTERS, 

 18 POST OFFICE SQUARE. 

 1898. 



