54 MIMICRY, AND OTHER PROTECTIVE 



lighter foliage, the blue and purple tints in its plumage 

 would far sooner betray it. The robin redbreast too, 

 although it might be thought that the red on its breasfc 

 made it much easier to be seen, is in reality not at 

 all endangered by it, since it generally contrives to 

 get among some russet or yellow fading leaves, where 

 the red matches very well with the autumn tints, 

 and the brown of the rest of the body with the bare 

 branches." 



Reptiles offer us many similar examples. The most 

 arboreal lizards, the iguanas, are as green as the leaves 

 they feed upon, and the slender whip-snakes are ren- 

 dered almost invisible as they glide among the foliage 

 by a similar colouration. How difficult it is some- 

 times to catch sight of the little green tree-frogs 

 sitting on the leaves of a small plant enclosed in a 

 glass case in the Zoological Gardens ; yet how much 

 better concealed must they be among the fresh green 

 damp foliage of a marshy forest. There is a North- 

 American frpor^' found on lichen-covered rocks and 



-~ A 



walls, which is so coloured as exactly to resemble 

 them, and as long as it remains quiet would certainly 

 escape detection. Some of the geckos which cling 

 motionless on the trunks of trees in the tropics, are 

 of such curiously marbled colours as to match exactly 

 with the bark they rest upon. 



In every part of the tiopics there are tree-snakes 

 that twist among boughs and shrubs, or lie coiled up 

 on the dense masses of foliage. These are of many 

 distinct groups, and comprise both venomous and 



