THE ENTOMOLOGIST. 



Vol. XVIIL] APKIL, 1885. [No. 263. 



ON SOME PKOBABLE CAUSES OF A TENDENCY TO 

 MELANIC VARIATION IN LEPIDOPTERA OF HIGH 

 LATITUDES, BY THE RIGHT HONOURABLE LORD 

 WALSINGHAM, M.A.-:= 



This address is a most welcome and instructive addition to 

 that branch of entomological literature which deals with variation 

 in the colour of insects. 



Melanic variation as exhibited in Lepidoptera from high 

 northern latitudes is chiefly dealt with, but similar variations of 

 colour in those from higli altitudes are adverted to, and topo- 

 morphic variations are incidentally mentioned. 



Speaking of the Lepidoptera of the Shetland Islands, Lord 

 Walsingham says : — 



" The tendency of this variation has in almost all instances been in the 

 direction of melanism (except in the more southern and western island of 

 Arran), exhibiting a preponderance of darkened scales or a suffusion of the 

 markings, in many cases almost obliterating the paler portions of the wing. 

 Among the species exhibiting this tendency in a greater or less degree may 

 be mentioned Hejnalus veileda, H. humidi, Noctua /estiva, N. xanthoijrapha, 

 Agrotis cursor ia, A. porphyrea, A. lucernea, Dianthcccia conspersa, Emme- 

 lesia albulata, Eiqnthecia vetiosata, E. tianata, Melanippe inontanata, 

 M. Jluctuata, Camptogramma bilineata, &c. This same tendency is ob- 

 servable in the majority of the Lepidoptera, and, I believe, of the Coleoptera 

 of the whole Arctic and sub-Arctic regions when contrasted with their more 

 southern repi'esentatives." 



* Being the Annual Address of the President to the Members of the Yorkshire 

 Naturalists' Union, atDoncaster, March 3, 1885. 



ENTOM. — APRIL, 1885. M 



