192 MARKINGS, AND COLOUR CONTRASTS. 



appear on both upper and under surfaces of the wings and 

 the markings are nearly the same on both sides. In others, 

 as in the Callicorince, Catagravunime, Sac, ahhough the 

 insects are extremely brilliant and richly coloured on both 

 the upper and under sides, they are quite different in both 

 design and colouring on the two surfaces of the wings. 

 Sometimes the display of colour appears only on the 

 upper surfaces, as in the gorgeous MorphiiicB, Ornithopterce, 

 Papilionincs, &c., which are luxuriously adorned in iridescent 

 blues and greens, crimson and orange, with combinations 

 of other colours equally attractive to the eye, whilst the 

 under surfaces are comparatively dull and inconspicuous. 



In others of the Lepidoptera the upper surfaces of the 

 fore wings are much less highly coloured than those of the 

 hind wings, for instance in the Catocalce and many other of 

 the diurnal moths ; which rest with the upper surfaces of 

 the wings exposed, the grey fore wings folded over and 

 concealing the brightly coloured hind wings. 



On the other hand there are thousands of species of 

 butterflies and moths the appearances of which are quite 

 the opposite of those considered above. In place of the 

 gay and showy colours they are clothed in subdued grey 

 and drab, dun and umbre and dull brown, nearly uniform 

 over the whole surfaces of the wings, almost without 

 pattern, or marked with few and generally inconspicuous 

 and often obscure spots and bands. Many again are of a 

 greenish hue, or mottled in green and grey and are seen 

 indistinctly, or perhaps not at all, in the obscurity of their 

 natural surroundings. 



III. Insects as Food for other Animals. 



The increasing ratio of successive generations of insects 

 is so great that were it unchecked and all the young 



