in PROTECTIVE RESEMBLANCES AMONG ANIMALS 47 



this insect belongs, is more or less imitative, and a great 

 number of the species are called " walking-stick insects," from 

 their singular resemblance to twigs and branches. Some of 

 these are a foot long and as thick as one's finger, and their 

 whole colouring, form, rugosity, and the arrangement of the 

 head, legs, and antennae are such as to render them absolutely 

 identical in appearance with dead sticks. They hang loosely 

 about shrubs in the forest, and have the extraordinary habit 

 of stretching out their legs unsymmetrically, so as to render 

 the deception more complete. One of these creatures ob- 

 tained by myself in Borneo (Ceroxylus laceratus) was covered 

 over with foliaceous excrescences of a clear olive green colour, 

 so as exactly to resemble a stick grown over by a creeping 

 moss or jungermannia. The Dyak who brought it me 

 assured me it was grown over with moss although alive, and 

 it was only after a most minute examination that I could 

 convince myself it was not so. 



We need not adduce any more examples to show how 

 important are the details of form and of colouring in animals, 

 and that their very existence may often depend upon their 

 being by these means concealed from their enemies. This 

 kind of protection is found apparently in every class and 

 order, for it has been noticed wherever we can obtain suffi- 

 cient knowledge of the details of an animal's life-history. It 

 varies in degree, from the mere absence of conspicuous colour 

 or a general harmony with the prevailing tints of nature, up 

 to such a minute and detailed resemblance to inorganic or 

 vegetable structures as to realise the talisman of the fairy 

 tale, and to give its possessor the power of rendering itself 

 invisible. 



Theory of Protective Colouring 



We will now endeavour to show how these wonderful 

 resemblances have most probably been brought about. Re- 

 turning to the higher animals, let us consider the remarkable 

 fact of the rarity of white colouring in the mammalia or birds 

 of the temperate or tropical zones in a state of nature. There 

 is not a single white land-bird or quadruped in Europe, except 

 the few arctic or alpine species, to which white is a protective 

 colour. Yet in many of these creatures there seems to be no 



