160 
[December, 
mountain in latitude 36° 30' I have taken a variety of this species, 
with an almost bright blue thorax, and here, on the 15th June last, I 
traversed snow at intervals, some feet in thickness, under the trees. 
The next species is D. Fortunei , found in lat. 38° 30', on Awasima, 
by the late Dr. Adams, and I will remark three things regarding it : 
the $ has the tarsi (in common with the next two species) very slightly 
dilated, the thorax is bronzed, and I presume it inhabits a colder climate 
than D. pandurus, as the Kuro-suwo, or warm stream of Japan runs 
up the east coast, and the west has no such pleasant influence. 
Recently, in latitude 41°, I have taken a series of a species with 
the head and thorax of a rich coppery-red hue, and elytra green and 
partly metallic. Finally, crossing the strait of Tsugar to the island of 
Yezo, we find D. rugipennis, another bright coloured species. Both 
the last are near allies, and agree with D. Fortunei in general outline 
and form of the tarsi. In the district of D. viridipennis, the new 
species, snow lies on the length and breadth of the land three or four 
months in the year, and there is frequently snow remaining on some 
of the higher mountains throughout the summer, and a similar, though 
somewhat colder, climate prevails in South Yezo. The mean tempera- 
ture in latitude 43° 3' 56" N. was, in January, 1878, at 7 a.m., 16° F., 
and in July, only 64°, and August, 65°, and the depth of snow {mean), 
January, 11 inches, and February, 48 inches. 
I am endeavouring to discover whether Damaster in any form exists 
on the north-east coast, in latitude 44°, for there the Kuro-suwo leaves 
the coast, and the sea in mid- winter is a mass of ice for two miles from 
the shore, and, following the rule of the others, a small highly coloured 
species would occur here, if the genus extends so far. 
Thus we see in tracing Damaster from the south to the north, 
species become smaller, and step by step modified in form, with colour 
appearing the higher we go, either in altitude or in latitude. In 
the mountains of central Nipon, we have the blue D . pandurus, and, in 
the north, metallic species. 
The general change of contour and tarsal development are 
divergences from the type easily explained by evolution, and, of course, 
the cause of colour may be bracketed, too, under the same general laws. 
In the south, the warm nights, with summers of tropical heat, are well 
suited for the large, nocturnal, black-coloured species we find there ; 
but the genus, in forcing its way north, must, as a warmth-loving 
creature, accommodate itself to circumstances. Passing from the 
tropics, it becomes either diurnal or crepuscular (for it gradually 
enters the regions of twilight), and assumes the colours we naturally 
