164 Distribution of Moths of the Sub-Family Bistoninae. 
II.—THE GENUS LYCIA. HUB. 
Lycia hirtania. (Cl.) Distribution :—North and Central 
Europe (excluding the Polar Regions), Central Italy, Balkan 
Peninsula, Turkestan, Asia Minor, Algiers, Tunis. 
Lycia ursaria (Walk.) Distribution :—In North America in 
the Northern portions of the Appalachian region, around the 
Great Lakes westward through Manitoba to Alberta, Labrador. 
As is clearly indicated above, the present pair of closely allied, 
although perfectly distinct forms are widely separated geograph- 
ically, one species occurring in the Western portions of the 
Palearctic area and the other in the Eastern parts of the 
Nearctic region. Undoubtedly, we are here concerned with a 
pair of what are generally termed representative species, 1.e. 
species restricted to different geographical areas and which have 
diverged and become species by reason of their long geographical 
isolation—a statement which imphes that at some period, these 
species were connected or occupied a continuous area of distrib- 
ution. This, as can be seen from the range of the two species as 
given above, is not the usual Holarctic range of species which 
have, for the most part, originated in Asia and have spread 
westward into Europe and eastward into America, for the group, 
other than as obvious overflows, does not exist in Asia. The 
connection then must have been between Europe and North 
America, either across the North Atlantic or via some long 
submerged Arctic continent far to the north. Judging from the 
northern character of the present group, in no point more strongly 
emphasised than in the proneness of the pupe to lie over for 
several years, in all probability, the connection they used was in 
high Arctic latitudes, a probability which of course does not 
exclude a possible land bridge by way of Iceland, Greenland and 
Labrador. 
Granting that the former bridge was that used, then we have 
a further proof if that were necessary, that the average annual 
temperature of the North Polar regions during Miocene and far 
into Pliocene times, was much higher than that which obtains at 
the present time. In all probability, Nova Zembla, Franz Josef 
Land and Spitzbergen are the sole existing relics of this connec- 
tion for their former continuity can be shown most beautifully 
from a consideration of their surviving Bryophytes. 
A land bridge having been shown a logical necessity to bring 
the present forms into contact, we are now face to face with the 
problem of the centre of dispersal of the genus. Three possibili- 
ties are open, (1) that the genus originated i in America ; (2) that 
it is of Arctic or Boreal origin ; (3) that it came into being in 
Europe. The first supposition can readily be dismissed when one 
considers that the whole Non-Boarmioid group of Bistonine has 
only two American representatives, one of which, Poecilopsis 

Naturalist» 
