460 
The Progress of the 
[October, 
sight-organs of inserts may differ from our own no less in 
mode of action than they do in structure, we should he pre- 
pared to expert that their perceptions may in nicety and 
accuracy surpass our own. Mr. Wallace himself, in his 
“ Contributions to the Theory of Natural Selection,” says 
“ their [inseCt’s] sight may far exceed ours both in delicacy 
and in range.” In the present work, also, Mr. Wallace treats 
of colour as affording a means of mutual recognition, of 
especial value to insects, though he adds that “ in birds 
such marked differences of colour are not required, owing 
to their higher organisation and more perfect senses.” Now 
we have certainly no faCts to prove that the sense of smell 
in birds ever attains anything like the delicacy and accuracy 
which are evinced in the case of certain inserts — those, for 
instance, who are caught by the stratagem of “ sembling.”* 
The brilliant and striking colouration of many berries 
Mr. Wallace considers may subserve the dissemination of 
the species. Birds attracted by the colour swallow the 
berry, and void the seeds in localities where they may take 
root. The same brilliant hues occur also, however, in 
larger fruits, where the seeds are never swallowed. Both 
birds and inseCts show that they are perfectly able to dis- 
tinguish a ripe cherry, plum, or peach from one that is still 
green, and generally confine their attentions to the more 
highly coloured sunny side ; but the stone is left hanging on 
its stalk. Consequently the possession of striking colours 
by the fruit, and the recognition of such colours by birds, 
wasps, butterflies, &c., does not aid in the multiplication of 
the tree. 
Mr. Darwin and Mr. Wallace both seem to agree that the 
highly-coloured spots on the wings of butterflies, being 
generally placed remote from any vital organ, may have a 
protective effeCt, causing birds to strike at these parts rather 
than at the head or body. If, however, we carefully con- 
sider the flight of a butterfly, we shall be inclined to doubt 
whether a blow aimed at the tips of the wings might not be 
quite as likely to fall upon the body. 
Public attention has lately been drawn to a point in the 
history of colour-perception in our own species, which at 
first sight seems to have an important bearing upon the 
antiquity of man and the rate of his intellectual develop- 
ment, as well as to throw a useful side-light upon sexual 
selection, upon mimetism, and other phenomena among the 
lower animals. It is well known that a large proportion of 
* Quarterly Journal of Science, vol. viii., p. 304 (July, 1878). 
