PROCEEDINGS 



OF THE 



GENERAL MEETINGS FOR SCIENTIFIC BUSINESS 



OF THE 



ZOOLOGICAL SOCIETY OF LONDON 



PAPERS. 



15. The Life-History and Habits of two Parasites of Blow- 

 flies. By A. M. Altson. With an Introduction by 

 Prof. H. Maxwell Lefroy, F.Z.S.* 



[Received Marcli 29, 1920 : Read April 13, 1920.] 

 (Text-figures 1-20.) 

 Index. 



Page 



A Short Account of the Start of the Work 196 



Breeding Methods 198 



Life-History and Hahits Alysia manducatoy^ Panz. and Hosts 199 



Life-History and Habits oi Nasonia hrevicornis Ashm. and Hosts ... 216 



Super-parasitism, or Accidental Secondary Parasitism 230 



Refrigerating Experiment 240 



Conclusions upon the Economic Importance of A. manducator 



Panz. and N. hrevicornis Ashm 241 



Summary 242 



Acknowledgments 243 



References 243 



Introductiox. 



This paper deals with part of the work initiated after a visit 

 to Australia, wdiere the lack of any means of control of the Sheep 

 Blow-flies is painfully evident. As some of these probably came 

 from England, it seemed desirable to study the natural checks 



* Communicated hy Prof. Lefeot. 



Proc. Zool. Soc— 1920, No. XY. 14 



