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UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 276 
Contribution from the Bureau of Enlbmolbgit >. 
L. O. HOWARD, Chief **v ^ 
Washington, D. C. PROFESSIONAL PAPER sJptehOier 29, 1^15 
THE PEA APHIS WITH RELATION TO 
FORAGE CROPS 
By 
J. J. DAVIS, Entomological Assistant, Cereal and Forage 
Insect Investigations 
CONTENTS 
Introduction 
Synonymy 
Identity of the species occurring in 
America 
Past history of the pest and its injuries 
Character of attack 
Effects on cattle of feeding them in- 
fested clover 
Distribution and origin 
Food plants 
Description 
Page 
1 
Life history , ... 26 
Page 
Field observations 26 
Generation experiments 27 
Hatching of the egg ........ 43 
Molting 43 
Age at which females begin reproducing 45 
Reproductive period 49 
Longevity 49 
Fecundity of viviparous females ... 49 
Sexual forms .......... 50 
Fecundity of oviparous females .... 51 
Natural control 52 
Methods of artificial control 54 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
