200 Mr. H. J. Elwes’s 
of opinion that it was perfectly distinct from embla, 
principally consist in the presence on the hindwing below 
of disa of a lie of crescent-shaped marks on the outer 
greyish coloured half of the wing. #mb/a in Europe never 
seems to have these, but in some parts of Eastern Siberia, 
in the province of Irkutsk, though not in Kamschatka, it 
has these markings more or less developed, and forms 
a kind of transition to disa. 
Specimens from this region undoubtedly led Ménétries 
to form a contrary opinion to that of so good a judge 
as Staudinger. I have often observed in similar cases 
that the difference of opinion of really competent judges 
on such questions can nearly always be explained by the 
different materials before them, and can usually be re- 
conciled when each has been able to see the same 
specimens. 
The geographical distribution of embla and disa is inex- 
plicable if we assume them to be two species, and is 
remarkable enough if we look on them as one. 
Disa has been found, so far as I know, only in Arctic 
Norway and the Kola peninsula, where it flies at sea level, 
and in the interior of Lapland, from Junkersdal in the 
upper part of Saltdalen, just within the arctic circle on 
the Swedish frontier, where Schoyen found it in July, to 
Karasjok and Muonioniska, where the late Mr. Meinertz- 
hagen took it recently on the 12th of June in quite fresh 
condition. Schgyen also reports it from Wojmsjoen and 
Wallengren from near Sorsele, both in Umea Lappmark, 
which is the most southerly record [ have. 
The only other locality which I know of for certain is 
near Laggan, in the Rocky mountains of British Columbia, 
where it is rare and local according to Mr. Bean. When 
I was there in July, 1898, its season was nearly over, but 
I saw two or three specimens, and caught one flying in 
open marshy pine woods, surrounded by marshy meadows, 
on the banks of the Bow river, two miles below Laggan. 
Its flight was quick, as described by Staudinger, who also. 
says that at Bossekop it was restricted to grassy marshes. 
It settles on grasses, on which no doubt its larva lives. 
The American specimens agree with the type of what 
Hewitson described as mancinus, and differ from European 
ones in having the chocolate band of the forewing some- 
what diffused through the cell, which therefore shows a 
chocolate tinge on both surfaces. A trace of this in the 
