UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 173 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



April 13, 1915 



THE LIFE HISTORY AND HABITS OF 



THE PEAR THRIPS IN 



CALIFORNIA 



By 



S. W. FOSTER and P. R. JONES, Entomological Assistants 

 Deciduous Fruit Insect Investigations 



CONTENTS 



Introduction 1 



History , 3 



Economic Importance 7 



Character of Injury 11 



Description 20 



Page 



Systematic Position 22 



Anatomy 23 



Life History and Habits 25 



Natural Enemies 51 



WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1915 



