102 



Fenn had exhibited two bred females of the species, which 

 very nearly approached the variety shown from Hartlepool. 

 Mr. Clark also mentioned a drab specimen from the Wood 

 Street portion of Epping Forest. 



Mr. J. Jenner Weir read a paper on " Isochromatous 

 Lepidoptera" (page 132). 



MARCH <)th, 1893. 

 J. Jenner Weir, Esq., F.L.S., etc., President, in the Chair. 



Mr, J, Jenner Weir, in exhibiting some specimens of 

 Diurnea fagella, Fb., which he had himself taken about fifty 

 years ago, said that in those days none but pale-coloured 

 specimens of the insect were found in the localities he 

 collected in. It appeared now that the specimens of the moth 

 taken near London were generally much darker, and Mr. 

 Adkin had stated, at the last meeting of the Society, that 

 he had of late years observed a decided increase in the 

 darkening of the wings of this species, Mr. R, Adkin 

 remarked that the specimens exhibited by Mr. Weir were 

 certainly as light as any now taken in the London district. 



As a proof of the mildness of the present spring, Mr. 

 Weir mentioned that his brother, Mr. Harrison Weir, had 

 captured an example of Vanessa io, L., at Sevenoaks, on 

 February 19th last ; and that Gonopteryx rhamni, L., was 

 flying in his garden at Beckenham on March 9th. Mr. Fenn 

 mentioned that G. rhainni had been noticed very commonly 

 in the neighbourhood of Leatherhead as early as the end of 

 February, and Mr. Billups said he had, on the previous day, 

 (March 8th) observed four specimens of this species on the 

 wing at Dulwich. 



A discussion ensued as to the probable occurrence of Poly- 

 mnmatus dispar, Haw., at Cambervvell nearly fifty years ago. 

 Mr. Fenn said that he had heard of specimens from Shooter's 

 Hill Wood, near Woolwich, and Mr. Tugwell mentioned two 

 specimens which he traced to the keeper of Saye and Seal 

 Park, Kent, also fifty, or more, years ago. Mr. Hawes ex- 

 pressed doubts as to these reports, but Mr. Barrett thought 

 that as the marsh-land of the Cambridge and Norfolk district, 

 which was the original home of the species, gradually became 

 drained and broken up, the butterfly, under the instinct of 

 self-preservation, would migrate to similar though less ex- 

 tensive spots, and Mr. Tugwell suggested the marshes in the 

 Canterbury neighbourhood as affording suitable food and 

 shelter. Mr. Tutt agreed with Mr. Tugwell, and inquired if 



