PROTECTIVE RESEMBLANCES IN LEPIDOPTERA 25 



when we look at the animal by itself, that the pro- 

 tection is effective and real. We cannot appreciate 

 the meaning of the colours of many animals apart 

 from their surroundings, because we do not compre- 

 hend the complicated artistic effect of the latter. A 

 caterpillar in the midst of green leaves may have 

 many brilliant tints upon it, and yet may be all the 

 better concealed because of their presence ; the ap- 

 pearance of the foliage is really less simple than we 

 imagme, for changes are wrought by varied lights 

 and shadows playing upon colours which are in them- 

 selves far from uniform. 



Francis Galton noticed this fact with regard to the 

 higher animals in 1851. * Snakes and lizards are the 

 most brilliant of animals ; but all these, if viewed at a 

 distance, or with an eye whose focus is adjusted, not 

 exactly at the animal itself, but to an object more or 

 less distant than it, become apparently of one hue 

 and lose all their gaudiness. No more conspicuous 

 animal can well be conceived, according to common 

 idea, than a zebra ; but on a bright starlight night the 

 breathing of one may be heard close by you, and yet 

 you will be positively unable to see the animal. If 

 the black stripes were more numerous he would be 

 seen as a black mass ; if the white, as a white one ; 

 but their proportion is such as exactly to match the 

 pale tint which arid ground possesses when seen by 

 moonlight.* ^ 



' Galton's South Africa, p. 187 (Minerva Library). 



