BOARMID^.-PSODOS. 255 



space being smoky whitish-grey with a yellowish gloss. 

 Body and legs black. 



Very variable in the degree of silvery-white shading, 

 which in the male is often almost absent, in some specimens 

 the wings being nearly unicolorous smoky-black. Also there 

 is a strong tendency to approximation of the first and second 

 lines below the middle, and to their being joined together by 

 a black bar near the dorsal margin. Sometimes the two 

 lines actually join, and the central dark band becomes 

 broken into a large costal and a small dorsal blotch ; this is 

 finely shown in specimens in the collection of Mr, R. Adkin 

 where also are others having this peculiarity in one wing 

 only, the other being normal. 



On the wing in Jane and July. 



Larva and Pupa apparently quite unknown. 



The moth is an inhabitant of the higher mountains, its 

 favourite altitude being from 2000 to 4000 feet above sea 

 level, though it has been found as low down as 700 feet. Here 

 it flits about in a very lively manner in the sunshine, every 

 now and then settling, to sun its wings, on some mouutain 

 plant or on the rocks. On one of the mountains in Perth- 

 shire Mrs. Fraser found it, in numbers, on one flat-topped 

 eminence, where some of the rocks were black and others 

 grey, while on the ground the peaty earth of the boggy 

 spots was enlivened with grey lichens. Here she particularly 

 observed that the blacker males chose the black rocks for 

 resting upon, where they were practically invisible ; and that 

 the more smoky and paler males settled invariably upon the 

 browner peat ; while the more silvery-grey lichens were the 

 chosen resting places of the females. 



Curtis {Brit. Ent.) says that it was first discovered before 

 the year 1825 by Dr. Hooker upon the summit of Schehallion, 

 Perthshire ; the only plants being TricJwstomum lamiginosum 

 (fringe moss) and t:i2^lac]inum fastiyiatum. Richard Weaver, 

 who found it on that and another mountain — probably Craig 



