The Descent of Man

Trimen writes to me, "no characters of mere
marking or coloration are so unstable in the
Lepidoptera as the ocelli, both in number and
size." Mr. Wallace, who first called my attention
to this subject, shewed me a series of specimens
of our common meadow-brown butterfly (Hipparchia
janira) exhibiting numerous gradations
from a simple minute black spot to an elegantly-shaded
ocellus. In a S. African butterfly (Cyllo
leda, Linn.), belonging to the same family,
the ocelli are even still more variable. In some
specimens (A, Fig. 53) large spaces on the upper
surface of the wings are coloured black, and
include irregular white marks; and from this
state a complete gradation can be traced into a
tolerably perfect ocellus (A1), and this results
from the contraction of the irregular blotches of
colour. In another series of specimens a gradation
can be followed from excessively minute
white dots, surrounded by a scarcely visible
black line (B), into perfectly symmetrical and
large ocelli (B1). (48. This woodcut has been