Technical Series, No. 24. 



U. S. DEPARTMENT OF AGRICULTURE, 



BXJREj^TJ Om KNTOIMOLOG-Y. 



L. O. 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. 



