88 The Colours of Animals. 



These caterpillars, however, escape observation by 

 their great similarity to brown twigs a resem- 

 blance which is heightened by their peculiar atti- 

 tudes, and in many cases by the existence of warts 

 or protuberances, which look like buds. Some, 

 however, even of these caterpillars, when very 

 young, are green. Again, some caterpillars are 

 white. These feed on and burrow in wood. The 

 Ringlet Butterfly also has whitish caterpillars, and 

 this may at first sight appear to contradict the rule, 

 since it feeds on grass. Its habit is, however, to 

 keep at the roots by day, and feed only at night. 



6. In various genera we find Black caterpillars, 

 which are of course very conspicuous, and, so far as 

 I know, not distasteful to birds. In such cases, 

 however, it will be found that they are covered 

 with hairs or spines, which protect them from most 

 birds. In these species the bold dark colour may 

 be an advantage, by rendering the hair more con- 

 spicuous. Many caterpillars are black and hairy, 

 but I do not know any large caterpillar which is 

 black and smooth. 



7. Brown caterpillars, also, are frequently pro- 

 tected by hairs or spines in the same way ; but, 

 unlike black ones, they are frequently naked. These 

 fall into two principal categories : firstly, those 

 which, like the Geometridce, put themselves into 

 peculiar and stiff attitudes, so that in form, colour, 

 and position they closely resemble bits of dry stick ; 

 and, secondly, those which feed on low plants, con- 



