PROCEEDINGS OF THE PERTHSHIRE SOCIETY OF NATURAL SCIENCE, 
109 
is very tough, and the larva, before pupation, leaves a hole 
at the one end for the exit of the moth, but so arranged, on 
the old mouse-trap principle, that it is quite easy for the 
moth to come out, but impossible for anything to enter 
from without. Perhaps it is, however, while in the larval 
state that insects are most open to danger, being then either 
a delicate morsel for birds, or else a nice and well-stored 
home where some parasitic fly may put its family out to 
board. A large number of larvae are green, corresponding 
to the leaves on which they feed. Others, again, are 
brown, imitating the bark or twigs of the trees on 
which they rest. These, by their colours, and many 
of the geometrae or loopers, aided also by the forms 
they assume, sticking themselves out rigidly on their an- 
nal prolegs from a stem or branch, are easily overlooked. 
I remember the first larva of Amphidasvs Betularia I ever 
had I got in rather a strange way. I was feeding some 
larvse of the Peeble Prominent (Notodonta Dvomedarius), 
and on giving them a branch of birch every day, I always 
examined very carefully the old food which I took out, for 
fear any larvse should be attached to the stems. One day, 
on removing the old food, I was much struck at seeing 
what I thought at first was a very remarkable growth,—a 
thick stem coming from one of smaller size,—but on tak¬ 
ing hold of it to examine it more closely, I was very m uch 
surprised on feeling a soft larva curl up between my 
fingers. It must thus have been attached to the branch 
when I cut it from the tree. Many observations and ex¬ 
periments have been made on larvse with birds, frogs, &c., 
the evidence of which I may state as briefly as possible. 
All larvae, such as I have just mentioned, which imitate in 
colour the leaves and stems of trees, are greedily eaten by 
birds. Spiny larvae, such as those of the Tortoiseshell and 
Admiral Butterflies, and also hairy larvae, such as those of 
the Tiger (Chelonia Caja), &c., are all rejected by birds; so 
that their spines and hairs are a protection to them. The 
colours of some larvae are bright and conspicuous, and 
these do not feed singly and on the undersides of leaves, 
&c., like those which mimic vegetation, but are usually 
gregarious in their habits, and seem by their very actions 
to court observation, such as Abraxas grossulariata, 
Diloba Ctxruleocephala , Euchelia Jacobecc, &c. These, at 
first, presented a difficulty not easy of explanation, but the 
experiments above referred to seem to have revealed the 
true use of their conspicuous colours. Larvae of these 
species were given to birds at various times,—sometimes 
mixed with others which were greedily eaten,—but these 
bright ones were always rejected and left to crawl away, 
shewing that they must have been distasteful to the 
birds ; and it has been suggested that in these 
cases their colours serve them good purpose, acting as 
danger-signals or warnings to birds that these are not 
edible. The only other instance of protective colouring 
among larvae I shall mention is that of the Emperor Moth 
{Saturniz carpint). The larva, in its earliest stages, re¬ 
sembles very closely the stems of the heather on which it 
feeds, and is also at this period covered over with a very 
fine down. Later on, when the heather presents a greener 
aspect, and the larva has changed several skins, we find it 
also robed in green, with a black band across each seg¬ 
ment. When the heather is in full bloom, and the 
larva is nearly full grown, it becomes spotted with bright 
pink, and so by its assimilation to the surrounding 
hea’her it evades much danger. Among the cases of 
protection afforded to insects by their actions, I would 
mention how many beetles and spiders, when danger is at 
hand, roll themselves up and feign death, and, when the 
danger has disappeared, quickly find their feet and make 
off. Many moths adopt the same course, the most re¬ 
markable of which that has come under my own notice 
being the Coxcomb Prominent {Notodonta camelina). Find¬ 
ing one morning a specimen on the top of the breeding- 
box, in which the cocoons were situated, I put my hand 
in, and, at the same time giving a sharp knock with the 
other hand on the outside, dislodged it from the top, when 
it fell into the palm of my hand. On examination it ap¬ 
peared quite lifeless, and I thought it must have been 
out for several days, and had died. I turned it over 
several times, and then threw it up a little, letting it fall 
as heavily as possible, but still no signs of life appeared. 
To make sure, I tried if its legs were rigid, and, on apply¬ 
ing my forceps to one of the feet, it gave a kick—the first 
evidence of life I had observed. I replaced it in the box, 
lying on its side, and, after being left for a time in quiet¬ 
ness, it soon righted itself. 
Of tropical insects I can only mention one or two. 
One of the most wonderful is certainly the Leaf 
Butterfly of India ( Kallima inachis), described by Mr 
Wallace. It is a large and beautiful insect, the 
ground colour being deep bluish, and having a broad 
band of orange across the wings. Its flight is quick, 
and when on the wing it is very conspicuous, but it 
has only to settle on a branch to be entirely lost 
to view, for the undersides, by their colours and the 
shape and position of the wings, give it the exact appear¬ 
ance of a leaf. Mr Wallace states that it seems to have the 
instinct to rest among dead and decaying leaves, so that 
this combination of colour, form, marking, habit, and in¬ 
stinct produce a degree of concealment which is perfectly 
startling. The Heliaonidse of tropical America is a group 
