204 THE HARMONIES OF NATURE. 



running larvae, from which, after incalculable losses, 'the winged 

 legions of the beetles and flies emerge, are likewise doomed to a 

 wingless state. Where food is always near at hand in inexhausti- 

 ble quantities, or w 7 here, as in the grasshoppers, the leaping 

 faculty is extremely developed, the powers of flight are propor- 

 tionally less active, while they appear to perfection in such vege- 

 table-feeders as are obliged to roam about constantly from flower 

 to flower, or in those predaceous insects that feed upon a 

 volatile prey scarcely less active than themselves. Thus we 

 see the dragonfly darting with the velocity of a hawk over 

 rivulets and ponds, over meadows and hedges, and rivalling the 

 sparrow in the extermination of gnats and flies. While it 

 performs its evolutions, the delicate transparent tissue of its 

 large gossamer pinions gleams in the broad sunshine with 

 all the colours of the rainbow; but still richer tints, a still 

 more gorgeous metallic brilliancy adorns the wings of many 

 beetles and butterflies. 



We admire the mosaic works of the Italian artists, where 

 thousands of minute stones are joined together with such con- 

 summate skill as to deceive the eye, and rival the finest 

 pictures in harmony of outline and colours ; but yet how coarse 

 are these masterpieces of human skill when compared with the 

 texture of the butterfly's wing, where countless scales, undis- 

 tinguishable by the naked eye, form patterns of the most ex- 

 quisite beauty! 



On examining a plate of mosaic through a microscope of very 

 moderate strength, it looks no better than the roughest patch- 

 work of a savage, while the unparalleled perfection of the butter- 

 fly's wing first comes to light under a strong magnifying power. 

 Then it is seen covered with regular rows of scales, each row 

 overlapping a portion of the next, so that the surface appears 

 tiled like the roof of a house ; and each scale shows itself regu- 

 larly marked by narrow longitudinal ribbings, and furnished 

 with a sort of handle at one end, by which it is fitted into a 

 minute socket attached to the surface of the insect. Each scale 

 consists of two superficial coloured laminaa, inclosing a central 

 lamina of structureless membrane, the surface of which is 

 highly polished, and which acts as a foil to increase their bril- 

 liancy by reflecting back the light that passes through them. 



Thus each scale is in itself a masterpiece of art, and many 



