vii DEFENCES OF INSECTS 247 



varied uses to which colour may be put among 

 animals ; or it would be more correct to say that, some 

 of these defences being adopted, the causes which lead 

 to the development of colour have been enabled to do 

 their work unchecked. It can easily be understood 

 how such defence may be in a measure so perfect as 

 to be adequate for all the wants of the race, and 

 ensure the maintenance of large numbers, in which 

 case the suppression of colour is no longer necessary, 

 and gorgeousness may be developed without harmful 

 effect. Hence among insects best protected in the ways 

 described is found the greatest amount of colour, or at 

 any rate little or no attempt at protective resemblance. 

 To give only one example, the common wasp, the 

 hornet, and many humble-bees which are armed with 

 a formidable sting, are all conspicuous, and not one 

 of the stinging Hymenoptera is coloured to resemble 

 an inanimate or vegetable object. 



Bright colour is not only developed for sexual and 

 like purposes ; paradoxical as it seems, it may be 

 of high protective value. It acts as a danger-flag, a 

 warning to enemies that the possessor is inedible. 

 This may at first appear to be an advantage to the 

 enemies rather than to the conspicuous forms, and so 

 militates against accounting for the rise and growth of 

 the character by the action of natural selection, for 

 natural selection cannot possibly produce any modi- 

 fication intended exclusively for the good of another 

 species. But the conspicuous insect is benefited by 

 its gaudy colour. It is at once recognised as 

 distasteful, and is unmolested. Had it resembled 

 its surroundings it would have been liable to be 



