t80 



THE CAUSES WHICH 



development of its red spotty cincture among the slaty Westmore- 

 land ciuo-s ; and Dr. Buchanan White finds the takes on Perth- 

 shire areas are much larger, with white pupils to the black-wing 

 eyes in the female, more like, indeed, the accredited type coming 

 to us from Central Europe, for this mountain waif is not reputed 

 to extend its lines of dispersion to the chilly auroral light. 



The May Orange Tip Butterfly in Southern Europe is some- 

 times dwarfed, and has the white on the inferior surface of the 

 fore- wings replaced by yellow, while inversely the White Ermine 

 in the north becomes yellow. One singular example, shown in the 



diagram, taken in the house of 

 Sir Patrick Walker, at Drums- 

 heugh, Edinburgh, at the end 

 of August, 1820, and figured 

 by Curtis in his elegant volumes 

 under that gentleman^ s appella- 

 spiLosoMA wALKERi (cue). ^'qj^^ approachcd in colour the 



A melanic aberration of tlie White Ermine, female BufE Ermine, and prC- 

 showing how tbe wing-spots beconie 



lines by uniting together. scutcd the appearance of the 



fore-wing spots run together 

 into longitudinal dashes. On the other hand, those stray specimens 

 oi U/ijjeria fulvaffotakenhy our London colleetorsare of a buff colour, 

 though farther north, where the species is commoner, they assume 

 an ochreous tint. Brown, again, is generally intensified into black 

 in the Highland moth fauna, and especially so in the common Dark 

 Arches Moth and its garden congener A", rnrea j so is it likewise 

 in many other swift evening-flyers I have frequently taken 

 meandering among the clammy ash boughs during the pro- 

 longed summer twilights. The warm sunlight fawn on the 

 Fritillary's wing in Northern Europe, by enlargement of the black 

 dots, runs into new patterns that are enhanced by paling or 

 deepening in the ground. This Avill be manifest on comparing 

 species captured along those northern limits of distribution that 

 pass through the United Kingdom and Scandinavia, with types 

 from more southern forest clearings. One specimen of the Queen 

 of Spain, taken in Norway, in particular, proved to be quite black 

 above, with the pearly spots beneath also confluent, forming streaks. 

 In Nemeobius Lucina, however, I think Ave see the converse ; 

 for some specimens of this woodland butterfly I took in the 



