132 THE COLOURS OF ANIMALS 



A careful comparison of all the pupse obtained in 

 the conflicting colour experiments showed that, when 

 the illumination of the two surfaces was equal, the 

 effective results were produced by that colour to 

 which the larger area of skin had been exposed, 

 whether the head formed part of that area or not. 

 Parti-coloured pupae were never obtained. It there- 

 fore appears to be certain that the skin of the larva 

 is influenced by surrounding colours during the sensi- 

 tive period, and it is also probable that the effects are 

 wrought through the medium of the nervous system. 

 This latter conclusion receives further confirmation 

 from other observations which will be described in the 

 next chapter (see pp. 142- ^1G). 



