314 TROPICAL NATURE 



over the lower at each side, thus affording complete protection 

 to the delicate tongue, the perfect action of which is essential 

 to the bird's existence. The humming-bird's tongue is very 

 long, and is capable of being greatly extended beyond the 

 beak and rapidly drawn back, by means of muscles which are 

 attached to the hyoid or tongue-bones, and bend round over 

 the back and top of the head to the very forehead, just as in 

 the woodpeckers. The two blades or laminae of which the 

 tongues of birds usually seem to be formed are here greatly 

 lengthened, broadened out, and each rolled up ; so as to form 

 a complete double tube connected down the middle, and with 

 the outer edges in contact but not united. The extremities 

 of the tubes are, however, flat and fibrous. This tubular and 

 retractile tongue enables the bird to suck up honey from the 

 nectaries of flowers, and also to capture small insects ; but 

 whether the latter pass down the tubes, or are entangled in 

 the fibrous tips and thus draw back into the gullet, is not 

 known. The only other birds with a similar tubular tongue are 

 the sun-birds of the East, which, however, as we shall presently 

 explain, have no affinity whatever with the humming-birds. 



Colours and Ornaments 



The colours of these small birds are exceedingly varied and 

 exquisitely beautiful. The basis of the colouring may be said 

 to be green, as in parrots ; but whereas in the latter it is a 

 silky green, in humming-birds it is always metallic. The 

 majority of the species have some green about them, especially 

 on the back ; but in a considerable number rich blues, purples, 

 and various shades of red are the prevailing tints. The 

 greater part of the plumage has more or less of a metallic 

 gloss, but there is almost always some part which has an 

 intenser lustre, as if actually formed of scales of burnished 

 metal. A gorget, covering the greater part of the neck and 

 breast, most commonly displays this vivid colour ; but it also 

 frequently occurs on the head, on the back, on the tail-coverts 

 above or below, on the upper surface of the tail, on the 

 shoulders or even the quills. The hue of every precious 

 stone and the lustre of every metal is here represented ; 

 and such terms as topaz, amethyst, beryl, emerald, garnet, 

 ruby, sapphire; golden, golden-green, coppery, fiery, glowing, 



