COMBINATION OF MANY METHODS OF DEFENCE 283 



but has not been equally successful. The means of 

 defence have been the response on the part of the 

 organism to the increasing attacks of enemies, and 

 the latter on their part have met the response by 

 increased vigilance, activity or boldness. Mr. Belt's 

 metaphor of the mutual selective action between dogs 

 and hares exactly explains the relation between these 

 highly-protected larvae and their enemies, and serves 

 to show why it is that less attacked larvae are also 

 less defended (see pp. 253-55). 



When we compare the elaborate defence of these 

 two much-persecuted larvae, with the far simpler and 

 less effective protection of many caterpillars which 

 are less subject to attack, we are made to realise the 

 pre-eminence of natural selection in moulding the 

 forms of life around us for their ceaseless mutual 

 Btrifc. 



