UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 276 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



September 29, 1915 



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 



Life history 



Field observations 



Generation experiments 



Hatching of the egg 



Molting 



Age at which females begin reproducing 

 Reproductive period ........ 



Longevity 



Fecundity of viviparous females . . . 



Sexual forms 



Fecundity of oviparous females . . . . 



Natural control 



Methods of artificial control 



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WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1915 



