24 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
walking-leaf moth. Surrounded as it is in its natural condition of life 
by so many leaves with which it harmonises both in colour and form, it 
is an extremely difficult matter to detect it. Its wings closely represent 
two leaves, and when the moth lies, as it does, with its wings partially 
open, the narrow strip of its body, which is seen between them, resembles 
the midrib of the leaf. Moreover, the head resembles in appearance a 
bud, whilst its legs are the exact counterparts of the stalks of the leaves. 
My last illustration of " protective resemblance " is that of a walking- 
leaf beetle, and the same remarks apply with equal force here. 
Before leaving this division of my subject I should like to say a few 
words generally on this question. A friend of mine, when discussing the 
matter with me the other evening, asked what better instance of protective 
resemblance could there be than a hare sitting in her form. I reminded 
him, in re^^ly, that protective resemblance in its highest state must not 
be fixed, but must be capable of adjustment, and that while the English 
hare could not alter her colour in response to her surroundings, there 
were other animals, as well as insects, that could. There are some 
frogs, for instance, that have that power. A party of three gentlemen, 
when looking for fossils on the south coast of England, came across a frog 
in a cavern, and they were much struck by its very dark colour. One of 
the party, being interested in natural history as well as in geology, placed 
it out on a light-coloured sandstone and put a temporary barricade round 
it to prevent it from getting away. In the course of half an hour he 
looked at it again, and found that in that short space of time the frog 
had changed from dark to light, corresponding with the colour of the 
sandstone ; and when, afterwards, it had been replaced in the cavern, in 
the course of a quarter of an hour it had assumed its original dark 
colour again. So, too, all fishermen know that trout caught in a stream 
with a dark bottom are much darker than those caught in a stream with 
a light bottom, and that fish can vary their colour as they pass from 
dark to light, and rice versa. There is also an instance on record proving 
that blind creatures are unable to respond to the colour of their surround- 
ings. M. Pouchet, a Frenchman, onee observed, when gazing into the 
sea-water, what seemed to him at first to be a single plaice, but a closer 
scrutiny revealed the fact that there were quite a number of these fish, 
but that the one which had attracted his attention was very much darker 
than the others. Prompted by curiosity he succeeded in catching the 
dark-coloured fish, and was much surprised to find that it was totally 
blind, the inference being that, as it could not see, it was unable to 
respond to the colour of iXs surroundings. 
Aggressive RESEMBLA^x'E. 
We now pass on to aggressive resemblance." The first illustration 
of this division is that of an Asiatic lizard, which I have chosen as an 
interesting variation, as it is unnecessary for my purpose to confine my 
remarks entirely to insects or to animals of this country. In the illustra- 
tion, the colour of the lizard harmonises well with the colour of the sand 
on which it lies. Growing on the sand are little red flowers which insects 
love to visit. The lizard itself is partial to these insects. On either side 
