540 



THE WONDER OF LIFE 



Kallima, which is conspicuously coloured on the upper 

 surface, but becomes like a withered leaf when it folds 

 its wings together and exposes the brown under surface 

 (Fig. 11). As we have noted, the nervures on the wings look 



Hke the veins on a 

 leaf, and the sug- 

 gestion of a mid- 

 rib increases the 

 resemblance. 

 Spots on the 

 wings look like 

 holes on the leaf, 

 and so on. In 

 fact, perfection is 

 attained by the 

 combination of a 

 number of items. 

 Even the fact 

 that the colora- 

 tion of the under 

 surface and the 

 position of spots 

 may vary a httle 

 is perhaps ad- 

 vantageous, since 

 the butterfly has 

 thus a general 

 resemblance to different kinds and states of withered leaves. 

 Protective colour-resemblance is seen at its best in cases 

 where the animal can adjust itself to the coloration of the 

 surface on which it is resting ; and there is no better illus- 

 tration than that of plaice and other flat-fishes, which are 



Fio. 85. — Two spiders : I. Caerostris mitralis 

 like a knot on a twig ; and II, Ornitho- 

 soatoides decipiens, like a bird's dropping. 

 {After Vinson and Piokard-Cambridge.) 



