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A STUDY OF THE CAPSID BUGS FOUND ON 



APPLE TREES. 



By F. R. PETHERBRIDGE and M. A. HUSAINi. 



School of Agriculture, Cambridge. 



(With Plates IX— XI.) 



CONTENTS. 



1. Introduction .... 



2. Methods 



3. Capsids found on apple trees and their distinguishing 



features .... 



4. Plesiocoris rugicollis (Fieb.) 



Synonym j^ .... 



Adult 



The egg .... 



Instars .... 



Table of measurements 

 Table of duration of each stage 

 Habits .... 



Time and nature of injury 

 Cause of injury 

 Control .... 



5. Summary of the life-history of a capsid 



6. Orthotylus marginalis (Rent.) 



7. Psallus ambiguus (Fall.) 



8. Atractotomus mali (Mey.) 



9. The enemies of capsids 



10. The food of apple-dwelling capsids 



11. References 



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1. INTRODUCTION 



The damage done to apples by bugs of the family Capsidae has now 

 become a very serious trouble to fruit growers in this country and 

 a detailed knowledge of those found on apple trees is therefore of 

 immediate importance. This work was undertaken at the suggestion of 

 Fryer who has, during the past few years, made observations on these 

 insects (11, 12, i2a). 



^ Mr Husain wishes to thank the Government Grant Committee of the Royal Society 

 for the grant given to him to carry out this work. 



