AND ANATOMY OF CERTAIN HYMENOPTERA PARASITICA. 413 



Summary. 



1. Notes are given on the bionomics of certain Chalcididse, Briuionidse, 

 Proctotrypidse, and C-jnipidse, especially o£ Microgaster connewus, Mesochorus 

 pallidus, and Aphidius sp. 



2. Microgaster connexus (Nees) is a Braconid parasite on the larvae of the 

 moth Porthesla similis. 



3. Mesochorus pallidus (Brisch.) is a hyperparasite on the larvse of Micro- 

 gaster which live inside the larvse of the moth Porthesia similis. 



4. Notes and descriptions of part of the life-history of Apanteles 

 glomeratus, allied to M. connexus, are also given. 



5. Microgaster hiys from sixteen to fifty eggs inside the body of small 

 larvoe of Porthesia similis. In rare cases very few eggs are laid, while in 

 other examples sixty larvae were bred from one parasitized moth caterpillar. 

 Average number about thirty. 



6. The anatomy of the larvse is described. My account of brain, trachf al 

 system, gonads, silk glands, and gut broadly agrees with that of Seurat. 



7. Two tubes, called enigmatic tubular gLmds, are attached to the vesicle 

 near the gut and pass up the body J'orwards. They do not, as described by 

 Seurat, connect with the hind region of the gut. 



8. The heart is described ; it opens into the last segment of the body, 

 where it is very wide. 



9. The last abdominal "segment" is expanded into an enormous vesicle, 

 whose structure and minute histology is described. 



10. Two coiled tubes in the vesicle, described for the first time, appear to 

 be excretory in nature. 



11. No Malpighian tubes were found, but it was thought that the 

 enigmatic tubular glands might be modified Malpighian tubes (see pages 

 411-412). 



12. The gut and fat-absorption are described. The presence of food in 

 the gut is demonstrated clearly. 



13. The hyperparasite has been shown to oviposit, while the larval 

 Microgaster is from one-third to one-half full size. 



14. Certain facts with regard to the habits of the hyperparasite Mesochorus 

 are given. 



15. Notes are given on Parasitism and Hyperparasitism among Aphidse. 



16. Figures of four insects bred from Aphids, and belonging to different 

 Families, are given. 



17. The presence of a peculiar embryonic membrane in Aphidius sp. 

 parasitic on Aphis pomi is described^ and its use pointed out. 



18. The subject of Entomophagous Parasitism in Hymenoptera is fully 

 discussed from the point of view of Microgasteridse and Aphidiidse. 



Department of Physiology, Oxford. 

 January 28, 1918. 



