THE BRITISH RACES OF BUTTERFLIES. 133 
tions, in which the rust-colouring is still more reduced or entirely 
absent. 
Perfectly distinct races do not exist, the different forms occurring 
together in different proportions and with intermediate individuals, 
which tend to one or the other according to localities. One can con- 
sider as nymotypical the races which produce the nymotypical form 
tolerably frequently ; these are decidedly rare; the Vosges in France 
and the Harz in Germany are about the only localities in whieh it 
occurs; in the rest of Continental Hurope cassiope greatly predominates 
and, when transitional specimens to true epiphron occur, they are scarce 
and do not attain its complete development. 
The chief characteristic of the British race is its individual varia- 
bility, the three forms mentioned above occurring together, although 
the nymotypical one is always much smaller in size and does not reach 
the highest degree of development met with in the nymotypical race. 
' In the southern limits of its habitat the species tends to produce 
the mnemon form as the predominating one (Hautes-Pyrénées, southern 
Italy) and, strangely enough, it again is frequent near the northern 
limits (Scotland), or, at least, it is less rare there than in Central 
Europe. 
Erebia aethiops race caledonia, Verity, Bulletin de la Société 
Eintomologique de France, 1911, p. 811, pl. i., fig. 1. 
The nymotypical race from western Germany is intermediate 
between the extreme variations of this species ; the Alpine races do not 
differ much from it, but in the north of Italy two very distinct geo- 
graphical races occur in the hills; the gigantic tawrinorum, Verity, in 
the neighbourhood of Turin, and parvisi, Verity, in the province of 
Udine. In the north of Europe, on the contrary, the size of the species 
gets conspicuously smaller. 
I have described the Scotch race as follows :—KHasily distinguished 
from the Alpine race by its size, which is constantly lesser (expanse of 
wings 35mm.-42mm., whereas that of the type varies from 40mm. to 
45mm.), by its narrower and more elongated wings, with more acute 
angles and with the outer margin straighter; the fulvous (rust-coloured) 
band-like space is narrower and never contains more than three small 
ocelli, whereas in the Alpine race it often contains four or five ocelli, 
especially in the female sex; finally the band-like spaces on the under- 
side of the hindwings are frequently indistinct. 
This description applies to the typical series in my collection from 
Galashiels (Scotland), but in other Scotch localities transitional races 
occur, in which the characters mentioned above are not so highly 
developed. 
The leucotaenia, Stdgr., form, with very conspicuous white band- 
like spaces on the underside, is commonly produced by southern races, 
but does not occur, to my knowledge, in the British Islands. 
I have described a magnificent albino specimen in my collection, of 
German origin, under the name of semialbina, the costa and the mar- 
ginal area (outside the fulvous) is of a dirty white colour, the rest of 
the wing being light chestnut ; band-like spaces of underside white. 
(Lo be continued.) 
