-484 LEPIDOPTERA. 



rather lazily, usually at a height of ten feet or more, and is 

 not very often noticed on the wing for this reason. More 

 especially attached to woods, but the paler specimens may 

 not unfrequently be seen sitting on tree-trunks by the road- 

 side in any faii"ly-wooded district. Not uncommon in suitable 

 places throughout England and Wales, the creamy-white 

 form being that most generally distributed ; the ochreous- 

 brown race seems to be confined mainly to Southern districts ; 

 the grey to the Midland and Northern Counties and the 

 b)lack to the latter and to South Wales. In Scotland the 

 yellow-brown and dark brown forms are found in the large 

 woods of Perthshire, and various greyer and white varieties, 

 with the type, throughout the southern districts, Aberdeen- 

 shire, the Clyde Valley, Argyleshire and Sutherlandshire. 

 In Ireland it seems to be fairly common in all well-wooded 

 districts ; and there Mr. de V. Kane tells me that the brown 

 and creamj— white forms occur mixed together in May ; those 

 from the North of Ireland are often very prettily tinged in 

 various degrees with grey, or black dusting. 



Abroad it has a wide range throughout Central and 

 temperate Northern Europe, the North of Italy, Corsica, 

 Southern Russia, Bithynia, Tartary, the Corea, and Japan — 

 whence a rather full-sized form has received the name of 

 sxccllens — and where also small white and pale grey-brown 

 varieties are common. Also in China, and India — in a 

 suffused pale grey or yellow-brown variety with obscure 

 markings. Found also in all parts of North America from 

 Florida to Nova Scotia, but usually rather small and of a 

 dusky pale brown colour, and named occiduaria. 



While dealing at some length with the subject of variation 

 in colour in this species, I have not touched upon the subject 

 of the strictly modern character of the tendency to melanism 

 which this species, like Biston hctularius and some other 

 species, exhibits. Fortunately there is sufficient evidence 

 preserved to form a tolerable record of the change. In the 



