358 
THE GEOGRAPHICAL DISTRIBUTION OF THE 
MOTHS OF THE SUBFAMILY BISTONINAE. 
J. W. HESLOP HARRISON, M.Sc. 
(Continued from page 278). 
V.—THE GENUS NYSSIODES (OBERTHUR) 
Nyssiodes lefuarius (Erschoff). Distribution : — Japan,. 
Western China, the regions about the Amur river as far north 
as Okhotsk and as far south as Corea. 
. With the study of the present genus, we face for the first 
time the consideration of one of the oldest genera of the group. 
From this, one must not conclude that it has persisted as such 
unchanged during the whole of its existence. Undoubtedly, 
its enormous plumose antenne, the huge jawbone-like gnathos, 
the more slender and less hairy abdomen indicate its primitive: 
character. Nevertheless, the valves of the male genitalia are 
of the true Nyssie type to the oldest species of which, Nyssia 
zonania, it approximates in the very unusual combination of 
a velvety black abdomen with bright yellowish segmental 
incisions. 
Without entering into the phylogenetical connection of the: 
genera Wegabiston, Lycia, Palaeonyssia, Nyssiodes, Poecilopsis. 
and Nyssia, which is reserved for special treatmen., it is 
sufficient to say that in Nyssiodes, we are dealing with the 
remains of the line which linked up the forms with apterous 
females to the main Non-Boarmioid Bistonine linc. 
From the physiological remoteness of the genera Lycia and 
Nyssia, compared with the comparative nearness of Lycia and 
Poecilopsis, as betrayed by their partially fertile hybrids, and 
from the manifest relationsnip between Nvssta zonaria and 
N. lefuarius, the.e is but one conclusion to be drawn, and that 
is that the two latter forms, or what then represented them, 
must have a. one time been in contact. At present, if we look 
at the map, we find that tne nearest stations of the two insects 
are two thousand miles apart; if we replace zonaria by its. 
two nearest allies in the Poecilopsis group, i.e. P. rachelae and 
P. lapponaria, the distance is increased in both cases to four 
thousand miles, in the former case to the east, and in the latter, 
to the west. It is, however, certain that the contact must 
have been at the point of origin of the newer genera and, 
consequently, in the old Miocene and early Pliocene continent 
to the north of Europe and Asia. 
But this implies either that Nyssiodes has retreated from 
that point to its present stations, or that it has originated in 
the territory it now holds, and has spread northward, receding 
Naturalist 

