The injury done to the wheat in 1795 by the Tipula Tritici 

 (Cecidomyia B. E. 178) led to some valuable and interesting 

 observations published in the Linnean Transactions, whence 

 we learn that one, if not more, species of Platygaster are 

 destined to prevent the too extensive increase of the Tipulae. 

 As it would be impossible to do justice to Mr. Kirby's remarks 

 without transcribing the whole of his papers, we shall recom- 

 mend the perusal of them as well to the agriculturalist as to 

 the naturalist and philosopher. 



Mr. Walker has captured 50 species of this genus, and Mr. 

 Haliday has favoured me with the loan of his collection, and 

 proposes the following divisions. 



I. Scutellum produced or mucronated. 



1. P. filicornis Hal. MSS. 



2. P. Phragmitis Schr. Ins. Aust. p. 321. n. 647. Inhabits 

 the panicles of Arundo Phragmites. 



3. P. ruficornis Lat. Hist. Nat. v. 13. p. 227. 



4. P. velutinus Hal. 



5. P. hyemalis Curt. — Taken out of moss found in Coomb- 

 wood, the first week of January, by Mr. A. Mathews. It is 

 rather larger than P. TipulcS; the tips of the thighs, tibiae and 

 tarsi (excepting the fore legs) and antennae are black. 



6. P. Tritici Hal. 



7. P. Tipulae Linn. Trans, v. 4. 232. 8^ 5. 108. tab. 4./ 8 

 Sf 9. On grass in June, and on the glumes of the wheat in 

 July, when it deposits its eggs in the larvae of Cecidornyia 

 Tritici. 



II. Scutellum obtuse, tuberculiform. 



8. P. inserens Kirhy^ Linn. Trans, v. 5. p. 107. tab. 4. 

 f. 4 — 7. — June 7th, depositing eggs in the valvules of the 



corolla of the wheat, and when they hatch, attaching them- 

 selves probably to the larvae of C. Tritici. 



9. P. anthracinus Curt. Guide.- 



10. P. unicolor Curt. Guide. 



11. P. brunnipes Curt. Guide. 



12. P. consobrinus Curt. Guide. 



13. P. obscurus Walk. MSS. 



14. P. attenuatus Hal. MSS. 



15. P. elongatus Hal. — June and July, on grass at Southgate. 



1 6. P. inermis Hal. 



17. P. niger Hal. 



18. P. Boscii Jur. — Curtis. — This remarkable insect is sup- 

 posed by Mr. Haliday to be the female, and he suspects that 

 the males have no horns. Mr. Walker takes it from June 

 to August amongst grass in woods at Southgate ; it also inha- 

 bits umbellate flowers. 



The plant is Triticum {Agropyrum Beauv.) repensy var. 

 (Couch-grass). 



