226 - Observations on Pimpla })oinorum 



2. The larva of this Ichneumon is composed of a definite head and 

 thirteen trunk segments; no caudal process or anal vesicle is present. 

 Ten pairs of spiracles are evident but the pair situated on the second 

 segment is minute and vestigial, 



3. Pupation takes place within a slight silken cocoon spun within 

 the cavity of the unopened apple buds. The adult Ichneumons com- 

 menced to emerge on June ITth, and an average of twenty-three days 

 was occupied from the time of spinning the cocoon. 



4. The male insect was met with in considerable numbers for the 

 first time^ and its identity made certain. Hitherto nothing has been 

 known of this sex beyond Ratzeberg's surmise that a male Pimpla bred 

 by Nordlinger belongs to this species and that Catoni has reared it in 

 Italy. A full description of the male by Mr Claude Morley is included in 

 the present paper. 



. 5. After emergence in June, the biology of this species during the 

 rest of the year is unknown. Most probably it passes through a second 

 generation and utilises certain species of Lepidoptera as hosts. In 

 localities where Anthonomus pomorum is unknown both generations 

 probably parasitise Lepidoptera. 



6. From among 1270 apple buds gathered at Chatteris in Cambridge- 

 shire, and infested by the Apple Blossom Weevil, Pimpla pomorum was 

 found to effectively parasitise the latter to the extent of 27 per cent. 

 This ratio of parasitism is relatively high, and agrees very closely with 

 that found by Decaux to obtain among Braconid parasites of the same 

 host. 



7. It is suggested that measures involving the preservation and in- 

 crease of this parasite, along lines similar to those conducted in France, 

 should be given an adequate trial; it is likely that they may prove of 

 value as an accessory means of controlling the weevil. 



13. REFERENCES TO LITERATURE. 



Berthoumieu, G. V. (1894). Ichneumonides d'Europe et des pays limitrophes. Ami. 



Soc. Entom. France, pp. 241-274. 

 Catoni, G. (1912). Parassiti dcW Anthonomus pomorum (L.) osservati in valle di Non 



(Trentino). Boll, del Lab. di Zool. Gen. e Agrar. Porlici, vol. vi, pp. 148-150, 2 figs. 

 CusHMAN, R. A. (1913). The Calliephialtes parasite of the Codling Moth. Journ. Agr. 



Res. Washington, vol. i, pp. 211-237, PI. 20 and 14 text-figs. 

 (1916). Thersilochus conotracheli, a Parasite of the Plum Cui-culio. Journ. 



Agric. Res. vol. vi, pp. 847-856, pi. cix and 8 text-figs. 

 Elliott, E. A. and Morley, C. (1907). On the Hymenopterous Parasites of Coleo- 



ptera. Trans. Entom. Soc. Loud. pp. 7-75. 

 '(1911). Ibid. Fiist Supplement, T.E.S. pp. 452-496. 



