DIPTERA. 375 



seedlings had been destroyed. Tlie larvte appeared in groups of 

 three to five, and about three inches below the surface. 



Unfortunately the larvae, which accompanied the injured plants, 

 had become somewhat dry in transit, but one specimen of Bibio 

 appeared amongst the seedlings. This specimen escaped before I 

 could give it special attention, and the larvas all died in a few days. 



Specimens were also sent to Oxford by Mr Eobertson, and have 

 been identified by Mr. G. H. Grosvenor^ as Bihio johannis. 



It is generally supposed that the larvae of these flies are introduced 

 with manure or leaf-mould, but in this case no such dressing had been 

 applied to the plot for four years. It is also rather remarkable that, 

 in this case, the adjoining plot, which contained larch plants one year 

 older, were untouched. 



Many larvae of the Bihionidce are likely to be found during nursery 

 operations in spring, and the flies can very easily be hatched out, but 

 it Avould be well for the forester not over-conversant with systematic 

 details to send them to a specialist in Diptera, to ensure that the 

 species may be correctly determined. 



References to Liierature comidted. 



Biiinie, Francis G. On the AsphondyliiC of the Glasgow District. Nat. Hist. 

 See. Glasgow. 1876. 



Cambridge Natural History. Insects. Part II. 1899. 



Colliuge, Walter E. Report on the Injurious Insects of the Midland Counties. 

 1904-6. 



Collinge, Walter E. The Life-history of the Pear :\Iidge. 1905. 



Frank. Die Krankheiten der Pflanzen. 1896. 



Gardener's Chronicle, various articles from. 1870. 



Judeich and Nitsche. Forstinsektenkunde. 1895. 



MacDougall, R. Stewart. Proceedings of the Association of Economic Biolo- 

 gists. Vol. i., Part I. 1905. 



Niisslin. Leitfaden der Forstinsektenkunde. 1905. 



Theobald, Fred. V. An Account of British Flies. 1892. 



Theobald, Fred. V. Various miscellaneous writings. 



Verrall, G. H. A List of the British Diptera. 1901. 



Wingate, Rev. W. J. A List of Durham Diptera. Transactions of the Natural 

 History Society of Northumberland and Durham, vol. ii. 1906. 



^ Quarterly Journal of Forestry, July 1911. 



