446 HUMMING-BIRD 



The extraordinarily brilliant i^lumage which most of the Trochi- 

 lidse exhibit has been already mentioned, and in describing it 

 ornithologists have been compelled to adopt the vocabulary of the 

 jeweller in order to give an idea of the indescribable radiance that 

 so often breaks forth from some part or other of the investments 

 of these feathered gems. In all save a few of other birds, the most 

 imaginative writer sees gleams which he may adequately designate 

 metallic, from their resemblance to burnished gold, bronze, copper, 

 or steel, but such similitudes wholly fail when he has to do with 

 the Trochilidse, and there is hardly a precious stone — ruby, ame- 

 thyst, sapphire, emerald, or topaz — the name of which may not 

 fitly, and without exaggeration, be employed in regard to Hum- 

 ming-birds. In some cases this radiance beams from the brow, in 

 some it glows from the throat, in others it shines from the tail- 

 coverts, in others it sparkles from the tip only of elongated feathers 

 that crest the head or surround the neck as with a frill, while 

 again in others it may appear as a luminous streak across the cheek 

 or auriculars. The feathers that cover the upper pai-ts of the 

 bod}^ very frequently have a metallic lustre of golden-green, which 

 in other birds would be thought sufficiently beautiful, but in the 

 TrocMlidse its sheen is overpowered by the almost dazzling splen- 

 dour that radiates from the spots where Xature's lapidary has set 

 her jewels. The flight-feathers are almost invariably dusky — the 

 rapidity of their movement would, perhaps, render any display of 

 colour ineifective ; Avhile, on the contrary, the feathers of the tail, 

 which, as the bird hovers over its food-bearing flowers, is almost 

 always expanded, and is therefore comparatively motionless, often 

 exhibit a rich translucency, as of stained glass, but iridescent in a 

 manner that no stained glass ever is — cinnamon merging into 

 crimson, crimson changing to purple, purple to violet, and so to 

 indigo and bottle-green. But this part of the Humming-bird is 

 subject to quite as much modificatiou in form as in colour, though 

 always consisting of ten redrices. It may be nearl}!" square, or at 

 least but slightly rounded, or wedge-shaped with the middle quills 

 prolonged beyond the rest ; or, again, it may be deeply forked, 

 sometimes by the overgrowth of one or more of the intermediate 

 pairs, but most generally by the development of the outer pair. 

 In the last case the lateral feathers may be either broadly webbed 

 to their tip, or acuminate, or again, in some forms, may lessen to 

 the filiform shaft, and suddenly enlarge into a terminal spatulation 

 as in the forms known as " Eacquet-tails." The wings do not offer 

 so much variation ; still there are a few groups in which occur 

 diversities that require notice. The primaries are invariably ten 

 in number, the outermost being the longest, except in the single 

 instance of Aithurus, where it is shorter than the next. The group 

 known as "Sabre -wings," comprising the genera Campylopterus, 



