Technical Series, No. 24. 



U. S. DEPARTMENT OF AGRICULTURE. 



BXJRE^XJ OW ENTOnVLOLOGr^i". 



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



THE LIFE HISTORY OF THE ALDER 



BLIGHT APHIS. 



BY 



THEO. PERGANDE, 



Assistant. 



Issued April, 29, 1912. 



WASHINGTON: 



GOVERNMENT PRINTING OFFICE. 



1912. 



