126 



THE COLOURS OF ANIMALS 



while other larvse were exposed to each of the colours 

 for all three stages : the effects were then compared. 

 The results of the largest experiment of the kind are 

 given below : 



This analysis speaks for itself. Stages ii. and iii. are 

 both sensitive, but stage iii. is much less sensitive 

 than the other. This is proved by the fact that the 

 larvae which had been exposed to gilt surroundings 

 during stage ii. and to black afterwards, were lighter 

 thm those which had been exposed to black during 

 stage ii. and to gilt afterwards. In other words, the 

 coloured surroundings, both gilt and black, produced 

 more effect during stage ii. than iii. ; but both stages 

 are sensitive, because the black and gilt surroundings 

 produced still greater effects when they operated for 

 the whole period before pupation. It must be ob- 

 served that the caterpillars, in the experiment sum- 

 marised above, tended as a whole to produce the 

 lighter forms of chrysalides, so that the black did 



