viir ORIGIN AXD USES OF COLOUR IX ANIMALS 203 



known leaf-insects of Ceylon and of Java, species of Phyllium, 

 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 Avith 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 betAveen 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, Avhich was brought me in Borneo, was 

 covered with delicate semitransparent green foliations, exactly 

 resembling the hepati'ca? Avhich cover pieces of rotten stick in 

 the dam}) forests. Others resemble dead leaves in all their 

 varieties of colour and form ; and to show how perfect is the 

 protection obtained and hoAv important it is to the possessors 

 of it, the following incident, oljserved by Mr. Belt in Nicaragua, 

 is most instructive. Descril^ing the armies of foraging ants in 

 the forest which devour every insect they can catch, he says : 

 " I Avas much surprised Avith the behaviour of a green leaf- A 

 like locust. This insect stood immovably among a host of ants, 

 many of Avhich ran over its legs Avithout ever discovering there 

 Avas food AAdthin their reach. So fixed Avas its instinctive 

 knoAvledge that its safety depended on its immo\'ability, that 

 it alloAved me to pick it up and replace it among the ants Avithout 

 making a single eftbrt to escape. This species closely resembles 

 a green leaf." ^ 



Caterpillars also exhibit a considerable amount of detailed I 

 resemlilanco to the plants on Avhich they live. Grass -feeders ' 

 are striped longitudinally, Avhile those on ordinary leaves are i 

 ahvays striped obliquely. Some very beautiful protective 

 resemblances are shoAvn among the caterpillars figured in 

 Smith and Abbott's Lcpidojiterous Insects of Georgia, a A\^ork 

 published in the early part of the century, before any theories 

 of pi'otection Avere started. The plates in this Avork are 

 most beautifully executed from draAvings made by Mr. Abbott, 

 representing the insects, in every case, on the plants Avhich 

 they frequented, and no reference is made in the descriptions 

 to the remarkable protective details Avhich appear upon the 

 plates. We have, first, the larva of Sphinx fuciformis feeding 



^ The Naturalist In X icaragua, p. 19. 



