Proceedings 57 
Some species that feed upon the leaves of trees but descend 
to the ground for pupation are green until they are about to 
pupate, when, without casting the skin, they change to a dark 
grey or other colour that harmonises with the bark of the tree 
or the ground over which they pass before finding a suitable place 
for pupation. Thus they are specially protected at the important 
time of their lives when they have completed growth and are 
about to undergo the dormant period of their existence, during 
which the wonderful changes take place that transform the crawl- 
ing larva into the glorious flying imago. As an instance of this 
I will mention a Sphingid, Pachylia syces, Rothschild. The 
caterpillar is bright green, but it turns a smoky colour before 
descending to the ground. Another case of special interest in this 
connection, the change of colour to suit the different periods of 
the larval existence, is that of a large Saturnid ( Hediconisa caina). 
This species feeds upon an Eryngium that grows much in the 
manner of the pine-apple, with long sword-shaped leaves radia- 
ting from the centre and sheathing one over the other; and in the 
early stages the caterpillar is black, and it has the common habit of 
curling up and falling when disturbed; as in this case it falls into 
the dark recesses of the leaves, the dark colour is distinctly ad- 
vantageous. But after the last change the prevailing colour is 
green, and the caterpillar does not disappear amongst the leaves 
when disturbed. As in the case of Mo/ippa, this caterpillar is also 
protected by venomous spines. 
The next method of protection that I will mention is that of 
form that imitates surrounding objects; so well exemplified in 
the Stick caterpillars, the larve of the Geometridae; their re- 
semblance to short spurs from the stem of the plant on which 
they feed affording them protection from their enemies. The 
protection of form is naturally accompanied by that of colour; 
form alone if the colour was such as to call attention to the 
insect would be no protection at all. 
A combination of protective colour and form is well shown 
in a Limacodid \arva 1 took feeding on a Lauraceous shrub. 
When it has devoured the whole of a leaf and still remains at- 
tached to the stalk and midrib, it might well be mistaken for 
the leaf itself, I was not fortunate enough to rear this species, 
