BIONOMICS OF CERTAIN HYMENOPTERA PARASITICA. 387 



Notes on the Bionomics, Embryology, and Anatomy o£ Certain Hymenoptera 

 Parasitica, especially of Microgastcr connexus (Nees). By J. Bronte 



GrATENBY, B.A., B.Sc, Senior Demy, Magdalen College, Oxford ; Senior 

 Assistant in Zoology, University College, London. (Communicated by 

 E. S. Goodrich, F.R.S., Sec.L.S.) 



(Plates 24-26, and 15 Text-figures.) 

 [Read 2] st February, 1918.] 



Contents. 



Page 



1. Introduction to Section on Microgastei- connexus (Nees) 387 



2. Bionomical Note and Previous Work 388 



3. Personal Observations : — 



a. Material and Method 392 



b. The External Morphology of the Larvse 392 



c. The Anatomy of the Larvse 394 



d. The Alimentary Tract 394 



e. The Spinning Glands and Imaginal Discs 396 



/. The Heart 396 



g. The Nervous System and Gonads 396 



h. The Abdominal Vesicle 397 



i. The Fat-body '. 399 



4. The Tracheal System 399 



5. The Malpighian Tubes (?) of Seurat 399 



6. Embryonic Membranes of Microgaster 400 



7. The Segmentation of the Larval Microgaster connexus 400 



8. A Hyperparasite {Mesochorus iiallidus, Brisch.) of Microgaster connexus . 401 



9. The Position of the Hyperparasitic Larva in the Parasitic Larva 402 



10. Hyper-hyperparasites and other Hyperparasites associated through 



Microgaster and Mesochorus, etc. with Porthesia and Pieris 403 



11. Note on Parasitism, Hyperparasitism, etc., by Hymenoptera among 



Aphidfe (Plant Lice) 403 



a. The Parasitic Aphidius 406 



h. Hyperparasitic Chalcids and Cynipids , < 407 



c. Hyper-hyperparasitic Larva , 407 



12. Discussion 408 



13. Some Speculations with regard to the Morphological Identity of the 



Vesicle of Microgaster 411 



14. Summary 413 



15. Bibliography 414 



16. Explanation of the Plates 415 



Introduction to Section on Microgaster connexus (^Nees). 



In a previous communication (11) I reviewed our knowledge of the poly- 

 embryony in parasitic Hymenoptera. In the polyembryonic species the host 

 larva contains from fifty to one hundred or more parasitic larvae derived 

 LINN. JOURN. — ZOOLOGY, VOL. XXSIII. 28 



