HABITS OF TWO PARASITES OF BLOW-FLIES, 



243 



(4) Nasonia can act as an accidental secondaiy parasite upon 

 A. manducator if and when puparia containing the latter are 

 within its limited reach. 



(5) Both parasites in their hibernating stage — i. e., full-grown 

 larvae — can successfully Withstand over 6 weeks at 2"^' C. 



(6) Alysia manducator appears to be a more important parasite 

 as a natural control for the Blow-fly than Nasonia hrevicornisy 

 which appears to be itiore effective as a natural control of Diptera 

 which constantly breed in permanent refuse- and garbage-heaps^ 

 and where hosts w^ould be within crawling distance, such as 

 primarily the Common House-fly, Musca domesiica. 



A CKNOWLEBGMEXTS . 



To Miss Cheesman, Curator of the Insect House of the 

 Society's Gardens, Regent's Park, the writer is indebted for 

 the original lots of material from which the parasites emerged, 

 and for her assistance in procuring additional supplies of both 

 blowflies and parasites. 



To Mr. J. Waterston, Natural History Museum, the writer's 

 thanks are due for identifying the parasites. Acknowledgments 

 are also due to Mr. C. Gunns, Head Laboratory Assistant at the 

 Imperial College (Zoology Dept.) for assistance in maintaining 

 supplies of cages, breeding and feeding materials. 



References. 



1. Graham-Smith, G. S. — "Observations on the Habits and 



Parasites of Common Flies." Parasitology, June 1916. 



2. Froggatt, W. AV. — Miscellaneous Publication No. 1716. 



"The Sheep Maggot-fly {CaUiphora rujifac'ies) and its 

 Parasite," Agricultural Gazette of New South Wales, 

 Feb. 2, 1914. 



3. Marshall, Rev. T. A. — " A Monograph of British Braconida3," 



Part Y. The Transactions of the Entomological Society 

 of London. 1894. 



4. Graham-Smith, G. S. — " Further Observations on the Habits 



and Parasites of Common Flies." Parasitology, Oct, 1919. 

 6. Gatenby, J. Bronte. — "Notes on the Bionomics, Embryo- 

 logy, and Anatomy of Certain Hymenoptera Parasitica." 

 Journal of tlie Linnean Society, No. 224, June 30, 1919. 



6. Girault, a. a,, and Saunders, G. E. — " The Chalcidoid Para- 



sites of the Common House- or Typhoid -fly [Musca 

 domestica Linn.) and its xVllies." Psyche, Dec. 1909 and 

 Feb. 1910. 



7. Froggatt, J. L. — -"An Economic Study of Nasonia hrevi- 



cornis, a Hymenopterous Parasite of Muscid Diptera. 

 Bull. Ent. Research, March 1919. 



8. Froggatt (1915).— Extracted by Graham-Smith, G. S. (1). 



9. Waterston, J. — "Notes on the Morphology of Chalcidoidea 



bred from Calli])hora." Parasitology, vol. ix. No. 2, 

 Feb. 26, 1917. 

 Proc. Zool. Soc— 1920, No. XVII. 17 



