WARNING COLORATION. 107 



quite incommensurate with the size of the wound, or the pres- 

 sure of the blood may force out the viscera ; hence the means 

 of protection are chiefly passive, depending upon concealment 

 or advertisement by warning colours. 



I have myself noticed that a caterpillar twice bitten by a 

 large spider crawled away apparently unconcerned ; in these 

 cases, therefore, the disagreeable taste itself is the protection, 

 and not the brilliant colours. In many cases the supposed 

 protection afforded by the warning colour is reinforced by other 

 means of defence. Mr. Wallace accounts for the development 

 of warning colours by the need for advertisement of dangerous 

 or uneatable qualities. I do not see the absolute necessity for 

 this, excepting only if various other causes should prevent the 

 caterpillar from having recourse to protective coloration. 

 Moreover, evidence has been got together by Mr. Poulton 

 which proves that one species of protectively-coloured larvae 

 at least is uneatable. 



The instance which he brings forward is Mania typica, but 

 other examples are given from other orders of Arthropoda, and 

 I have referred to a few above. 



Insects with Warning Colours often protected in Other Ways. 



In the Magpie caterpillar the habit of feeding upon many 

 kinds of shrubs may be an adequate set-off against its con- 

 spicuous appearance ; and the same remark will apply to 

 Acronyctapsi (the Dagger moth), and to the Buff-tip caterpillar. 

 A considerable toll might be taken by many destroyers of insect 

 life (among them ichneumon flies, which do not avoid gaudily- 

 coloured caterpillars) without unduly diminishing the numbers 

 of these insects. With regard to the Magpie moth, I have 

 noticed that, like other Geometers, they do not begin to feed 



