VIII 
ORIGIN AND USES OF COLOUR IN ANIMALS 
203 
known leaf-insects of Ceylon and of Java, species of Phy Ilium, 
are so wonderfully coloured and veined, with leafy expansions 
on the legs and thorax, that not one person in ten can see 
them when resting on the food-plant close beneath their eyes. 
Others resemble pieces of stick with all the minutiae of knots 
and branches, formed by the insects’ legs, which are stuck out 
rigidly and unsymmetrically. I have often been unable to 
distinguish between one of these insects and a real piece of 
stick, till I satisfied myself by touching it and found it to be 
alive. One species, which was brought me in Borneo, was 
covered with delicate semitransparent green foliations, exactly 
resembling the hepatic® which cover pieces of rotten stick in 
the damp forests. Others resemble dead leaves in all their 
varieties of colour and form; and to show how perfect is the 
protection obtained and how important it is to the possessors 
of it, the following incident, observed by Mr. Belt in Nicaragua, 
is most instructive. Describing the armies of foraging ants in 
the forest which devour every insect they can catch, he says : 
“ I was much surprised with the behaviour of a green leaf¬ 
like locust. This insect stood immovably among a host of ants, 
many of which ran over its legs without ever discovering there 
was food 'within their reach. So fixed was its instinctive 
knowledge that its safety depended on its immovability, that 
it allowed me to pick it up and replace it among the ants without 
making a single effort to escape. This species closely resembles 
a green leaf.” 1 
Caterpillars also exhibit a considerable amount of detailed 
resemblance to the plants on which they live. Grass-feeders 
are striped longitudinally, while those on ordinary leaves are 
always striped obliquely. Some very beautiful protective 
resemblances are shown among the caterpillars figured in 
Smith and Abbott’s Lepidopterous Insects of Georgia, a work 
published in the early part of the century, before any theories 
of protection were started. The plates in this work are 
most beautifully executed from drawings made by Mr. Abbott, 
representing the insects, in every case, on the plants which 
they frequented, and no reference is made in the descriptions 
to the remarkable protective details which appear upon the 
plates. AVe have, first, the larva of Sphinx fuciformis feeding 
1 The Naturalist in Nicaragua, p. 19. 
