( xxi ) 



near the apex, and four in an inner transverse row close 

 behind the former, so arranged that the intervening black 

 colour occupies the same relative positions as the black spots 

 and black nervules of ovdmary thi/sbe ; these last-mentioned 

 specimens being thus intermediate between the oi"dinary S 

 and the aberration with the all-black tip described by JMr. 

 Trimen. 



" The hind-marginal border of orange-colour in the hind- 

 wing also varies considerably in width and extent, the portion 

 towards the costa being sometimes wanting altogether, some- 

 times represented by a spot or two of orange ; and the band 

 itself being sometimes continuous and sometimes divided by 

 crossing black lines on the nervules. 



"In some instances the brilliant 'shot' blue i"eiiection 

 extends over the orange band almost to the hind marginal 

 border. Fi^eshly emerged specimens were taken at different 

 times during the season from Oct. 22, 1899, to the 23rd of the 

 following February, so that it would appear that this dark 

 variety was not confined to one brood or one part of the 

 season. 



" The facts above-mentioned seem to justify us in regai-ding 

 this mountain form as a distinct dark variety rather than an 

 accidental ' sport.' 



" During the same season, whilst in pursuit of the ordinary 

 Z. thysbe on the Sand Hills near Minzenberg at about sea- 

 level, I found in the same locality as thyshe, four specimens 

 — one c^, 3 $ , which exhibit a different variation, somewhat in 

 the direction of Z. osbecki. The white spots, so conspicuous 

 on the costa and on all the fringes of ordinary thysbe, are 

 entirely absent, whilst on the underside of the hind-v\'ing the 

 markings are very faint indeed, almost obsolete, and the silver 

 colouring of the lititrx. entirely absent or only appearing (in 

 one specimen) in a few faint scales, and the whole of the hind- 

 wing and apex of the fore-wing look as if they had baen well 

 painted over with a soft clay-coloured wash which had almost 

 obliterated all the usual markings, the faint lines only remain- 

 ing distinguishable. The tint of this colouring approximates 

 closely to that on the underside of the hind-wing in pale 

 specimens of Z. 2)yrois. This variation was taken quite at 



