1889. ] MR. A.G BUTLER ON A NEW FOSSIL MOTH. 293 
In the list of Insect-remains determined by the late Mr. Frederick 
Smith of the Zoological Department, two Lepidopterous insects, re- 
ferred to a species of Lithosia, are recorded. 
The fossil now to be described is especially interesting on account 
of its unusually perfect condition, which not only enables one to 
trace without difficulty the main features of its structure, but gives 
a very good idea of its pattern and colouring when living. 
A study both of fossil and recent Lepidoptera leads one to the 
conclusion that the Butterflies and Moths of the past were by no 
means so highly coloured as those of the present day ; that in the 
earlier ages of the world the large family Nymphalidee was repre- 
sented by brown and black species, the Pierinze by species wholly 
white, or white bordered with black; the Hesperiidee and most, if 
not all, of the Moths by brown, black, and white forms. Even at 
the present day these three types of colouring are far in excess of 
more brilliant hues, and the fact of dull coloration being, as a rule, 
more abundantly found in female than male Lepidoptera, even in the 
more brightly coloured genera, tends to prove that sexual selection 
has been the principal agent in beautifying the species now existing. 
The Lepidopteron found by Mr. A’Court Smith belongs to the 
Euschemide, a family of Geometrid Moths allied to the Zerenidz 
(popularly called Magpie moths) and containing some of the most 
brilliantly coloured of all known Heterocerous Lepidoptera ; it, 
however, does not belong to the brilliant section of the family, but 
to a small group of genera for the most part black and white to the 
present day, though some of them have acquired yellow markings. 
Assuming that the Euschemide originally consisted of black and 
white insects, yellow would naturally be the first departure, on 
account of its being contained in the largest proportion in white’ ; 
and it would follow that in this family yellow markings would be 
most likely to preponderate at the present time, as, in fact, they do, 
whilst the black portions of the wing when modified show a violet 
or, in the more highly specialized forms, a bright blue shot tint. 
Mr. A’Court Smith’s discovery belongs to a group of three or 
four genera which to this day retain their original neutral tints of 
black and white, and which therefore are in all probability the oldest 
existing representatives of the family Euschemide ; these genera are 
Calospila, Simena, Mniocera, and Craspedosis ; other genera pro- 
bably remain to be discovered. 
It is a significant fact, as evidencing the permanence of Lepido- 
pterous forms, that, although at the present time we have numerous 
brilliantly coloured species and even genera, the primitive forms still 
have their representatives in nearly allied genera, the colours of which 
remain dull and the patterns but little modified. This is most easily 
seen in the best preserved and more recent fossils, such as Neorinopis 
represented by the black and white Neorina, Mylothrites by the brown 
forms of Precis, the so-called Pontia freyeri by the females of the 
S.-American P. suasa, and Thanaites by Thanaos ; the affinities of 
? White light contains a proportion of about 7’; yellow. 
Proc. Zoor. Soc.—1!889, No. XX. 20 
