50 FORM AND COLOUIl. 



missing the butterfly which loses a part of its wing but escapes alive. This 

 may seem to be a fantastic explanation, but it is borne out by good evidence. 



Other butterflies are perhaps coloured in rough imitation of their 

 surroundings as seen from above, i.e. } their colouring blends with the 

 light and shade of vegetation when they are looked at from above as a 

 bird looks at them. We cannot be certain of this since we see them 

 from about their own level, but the explanation of the colouring of many 

 butterflies is probably to be found in this. A few insects have apparently 

 a scheme of colouring that is meant to terrify an enemy or frighten it 

 away. Such are the Hawk Moth Caterpillars, which when alarmed sud- 

 denly expose large eye-like spots and look like a ferocious snake ; others 

 simply look bizarre and fearful, if we can judge from what we imagine a 

 bird feels when he encounters one. Many caterpillars have such devices, 

 coloured spots and stripes, brightly coloured filaments, waving hair tassels 

 and the like. 



These are the principal colour schemes found in insects, but still we 

 are ignorant of the significance or value of the colouring of many insects, 

 Ground beetles are commonly black or very dark coloured, perhaps because 

 they live in hiding. Many are white, especially those which come out 

 in the dusk, and this may facilitate courtship and mating. Colouring is 

 possibly not determined by utility in every case, but is simply for beauty, 

 and the general effect of insect colouring is, from man's point of view, 

 chiefly one of beauty. Possibly this is the case also from the insect's 

 point of view, and though necessity is considered, the whole scheme may 

 be primarily for beauty. 



FIG. 71. 



Lacewing Bugs ; their minute size is shown ly the hair line. 

 (No meaning except pure beauty can le assigned to their delicate ornamentation.) 



