TRIFID.-E. 211 



round, ill-defined, slate-grey, its margin rather streaked with 

 black but quite open below, where it joins a large slate-grey 

 cloud from the dorsal margin ; reniform stigma large, slate- 

 grey, edged with white and some black dots and streaks ; 

 costal margin distinctly and regularly spotted with black, 

 the last two spots towards the apex obscured, in another 

 smaller slate-grey cloud ; hind margin more faintly clouded 

 with the same, and edged with a series of short black streaks ; 

 cilia white, regularly chequered with slate-black. Hind wings 

 white, shaded with smoky-grey; central spot large, dull 

 black ; before the hind margin are two parallel smoky-grey 

 transverse stripes, forming a broad band, ill-defined, shaded 

 off, and frequently quite obscure, usually showing in its 

 extreme margin a series of white spots ; cilia dusky-white. 

 Female very similar, but the body stouter and more flattened ; 

 very often the slate-grey or blue-grey clouds of the fore 

 wings are more extended, and of a deeper tint, and the hind 

 wings more darkly shaded. 



Underside of the fore wings white round the margins, the 

 middle portion being occupied by a large smoky-black cloud 

 from which similar bars are thrown off to the costal edge ; 

 hind margin dotted with black and dusted with grey. Hind 

 wings white with the nervures black ; central spot elongated, 

 black; near the hind margin is an irregular, ill-defined, 

 cloudy-black transverse stripe. Body and legs white ; tibiee 

 barred with black. 



Variation in this species is in most localities but slight, 

 merely in the extension of the bluish-grey cloudy markings 

 on the white ground ; but in some places, especially upon the 

 coast, this is intensified, and the darkness of both fore and 

 hind wings in some of Mr. S. Webb's forms taken at Dover 

 is remarkable. Some equally dark, and even of a deep slate- 

 green or greenish-black tint, have been found in the neigh- 

 bouring town of Folkestone. From other places, both on the 

 coast and inland, specimens are obtained in which the slate- 

 grey markings are exchanged for yellow, or even pale orange, 



