U4: THE WOJRLD OF LIFE 



a depth and a purity of liue which seem to have reached the 

 limits of the possible. We may surely ask ourselves whether 

 these exquisite refinements of mere colour as well as the in- 

 finity of graceful forms, and the indescribable delicacies of 

 texture and of grouping, are all strictly utilitarian in regard 

 to insect-visitors and to ourselves. To them the one thing 

 needful seems to be a sufficient amount of difference of any 

 kind to enable them to distinguish among species which grow 

 in the same localitv and flower at the same time. 



Special Cases of Bird-colouration 



Coming now to birds, we find the colours with which they 

 are decorated to be fully equal in variety and purity of tint 

 to those of flowers, but extending still further in modifications 

 of texture, and in occasionally rivalling minerals or gems in 

 the brilliancy of their metallic lustre. The exquisite blues 

 and vinous purples, reds and yellows of the chatterers and 

 manakins, the glorious metallic sheen of the trogons, of many 

 of the humming-birds, and of the long-tailed paradise-bird ; 

 the glistening cinnabar-red of the king-bird of paradise, ap- 

 pearing as if formed of spun-glass ; the silky orange of the 

 cock-of-the-rock and the exquisite green of the Malayan crested 

 gaper, are only a few^ out of thousands of the extreme refine- 

 ments of colour with which birds are adorned. 



Add to these the marvellous ornaments with which the males 

 are so frequently decorated, the crests varying from the feath- 

 ery dome of the umbrella bird, to the large richly coloured 

 crest of the roval flvcatcher of Brazil, and the marvellous blue 

 plumes from the head of the fern-bearing bird of paradise 

 (Pteridopliora Alherti), with a thousand others hardly in- 

 ferior, and we shall more than ever feel the want of some 

 general and fundamental cause of so much beauty. 



All this w'ealth of colour, delicacy of texture and exuber- 

 ance of ornament, has been explained hitherto as being utili- 

 tarian in two ways only: (1) that they are recognition-marks 

 of use to each species, more especially during its differentiation 



