TRIFID^, 231 



wings dusky-white broadly tinged along the costal area with 

 purple ; central spot small, smoky-black ; beyond it is a 

 slender similar transverse line. Body purple-brown ; legs 

 dark-brown, tufts paler. 



Variation in this beautiful species is universal, hardly two 

 specimens are quite alike ; it shows itself in the tone and 

 intensity of the warm velvety-brown of the ground-colour, 

 and in its extent ; in the degree and extent of ashy -grey 

 clouding — which occasionally occupies the whole surface of 

 the fore wings except a central red-brown band — and espe- 

 cially in the longitudinal black striping. This is sometimes 

 remarkable, and is most seen in specimens from the Shetland 

 Isles ; the black basal streak is extended into a deep black 

 broad bar right through the wing to the subterminal line, 

 and is sometimes supplemented by a similar but narrower 

 broken stripe above it, or by long black dashes from the 

 reniform stigma to the same line, while in other instances 

 the centre of the wing is occupied by a black cloud, or all 

 the spaces between the nervures in this portion are filled in 

 with black, or, on the other hand, there is a total absence of 

 black markings. In examples from the Scottish mountains 

 many have large blotches of almost bluish or purplish bloom 

 at the base and on the costal or dorsal margins or both, and 

 very often along the hind margin, while some are devoid of 

 such shading altogether or lean toward rich dark purple- 

 brown with the markings obscured. 



Abroad the range of variation does not seem to be so great ; 

 those from the Swiss mountains are described as of a rosy- 

 brown ; from Lapland red-brown or rosy-grey ; from 

 Labrador dull inconspicuous brown, and from Finland ashy- 

 grey. 



On the wing from the end of June to the middle of 

 August. 



Larva cylindrical, tapering at the second segment to the 

 head and also at the thirteenth segment ; head glossy brown, 



