THE HUMMING-BIRDS, 281 



enabled to seize and bold insects. Says Martin : " It is by a pumping 

 or sucking action, as we have every reason to believe, that nectar or 

 liuids are absorbed by the tubular tongue of these birds. In no other 

 vertebrate animals, as far as we know, is the tongue constructed as a 

 tubular sucking-pump: so far, the humming-birds stand alone; and 

 this circumstance in itself, considering it with refei'^nce to organic 

 structure, might be adduced as a reason for regarding these birds as 

 a distinct order." 



Mr. Thomas Belt, author of "The Naturalist in Nicaragua," indi- 

 cates another function performed by the curious cleft tongue of the 

 humming-bird, viz., the capture of insects. As w^e have seen, this 

 organ is, for one-lialf its length, made up of a substance like rather 

 stitf parchment, or horn, and split in two. When at rest, the two 



Fig. 3. 



Tongue of Humming-bird, with Blades a little opened. 



halves are laid flat against each other, buL they can bo separated at 

 the will of the bird, and form a pair of forceps, admirably adapted for 

 picking out minute insects from among the stamens of flowers. 



We may admire the elegance of form and the quickness of motion 

 of these birds, but the dazzling splendor of their plumage, resembling 

 that of burnished metal or polislied gems, changing with every change 

 of position, has a charm for the dullest observer, and a fascination for 

 the more sensitive. The wonderful change in color that takes place, 

 according to the position of tlie light, from brilliant green, through 

 the brightest golden tints, to intense velvety-black, or from black to 

 emerald, or ruby, or crimson, or flame-color, reminds one of fairy-land, 

 or the tales of the genii. Where a metallic lustre prevails, the plu- 

 mage is always composed of feathers so shaped as to appear to have 

 the form of scales. The birds vary in respect to the parts that have 

 these feathers. While most have them on the throat, many have them 

 on tlie breast and head ; others have them also on the back ; some have 

 them on the wing-coverts or tail ; and a few have them on nearly all 

 parts, except the long wing-feathers, which are generally of a purplish- 

 brown. It may here be asked. What causes the gorgeous metallic 

 lustre of their plumage, and the rich, changing tints of the various col- 

 ors, representing every hue of the rainbow, purple, ametliyst, fiery 

 crimson, brilliant ruby, radiant topaz, emerald green, resplendent blue, 

 and glossy violet, which, in certain lights, often gleam with a reful- 

 gence that almost dazzles the eye? They have been attributed to 

 various causes ; but it appears to be the condition of the surface of the 

 feathers that produces the iridescence. The surface is striated, or has 

 minute furrows, like the nacre, or mother-of-pearl of the Ilaliotis^ and 

 other sea-shells, which decompose the light — absorbing part, and re- 



