458 



SYSTEMATIC SYNOPSIS. —PICABI^ — CYPSELIFOBMES. 



406. C.vaux'i (To Win. S. Vaux, of Philadelphia.) Vaux's Switt. Similar ; paler, the rump 

 and upper tail-coverts lighter than the rest of the upper parts ; the throat whitish. Smaller ; 

 length 4.50; wing the same; tail 1.67. Pacific Coast, U. S., and southward. Seems to be 

 different from pelasgica, but perhaps the same as a S. Am. species. Nesting and eggs as in the 

 common species. 



23. Family TROCHILID^ : Htunming-birds. 



X X. 



Fig. 298. — Humming-birds. (Prom Miohelet. ) 



Tenuirostrdl Picaria. These beau- 

 tiful little creatures will be known on 

 sight; and as the limits of this work 

 preclude any adequate presentation of 

 the subject, I prefer merely to touch 

 upon it. 



The Troehilidee, in all essential struc- 

 tural characters, are nearest related to 

 the Cypselidce. These two groups have 

 in fact been united by some in a super- 

 family Maerocfmes, in allusion to the 

 length of the hand and its feathers, and 

 tersely described as schuognathous In- 

 sessores. The flying-apparatus is as in 

 the swifts : a very deep-keeled sternum, 

 for attachment of powerful pectoral mus- 

 cles, a very short upperarm, but the 

 distal segments of the fore limb length- 

 ened, bearing a thin-bladed or even 

 falcate wing; primaries 10, the 1st 

 usually longest ; secondaries reduced to 6, and very short. Tail of 10 rectrices, but otherwise 

 too variable to be characterized, presenting almost every peculiarity in size and shape as a 

 whole, in size and shape of individual feathers, and often differing in form as well as color in 

 the opposite sexes of the same species. Feet extremely small and weak, unfit for progression, 

 formed exclusively for perching ; tarsi naked or feathered. Hind toe incumbent. Claws all 

 large, sharp and curved. The bill exhibits the tenuirostral type in perfection, being long and 

 extremely slender for its length ; it is usually straight, subulate or awl-shaped, or with lancet- 

 shaped tip ; it is often decurved, sometimes recurved, and again bent almost at an angle ; in 

 length it varies from less than the head to more than all the rest of the bird. The cutting 

 edges of the mandibles are inflected : the rictus is devoid of bristles. The nostrils are linear, 

 with a supercumbent scale or operculum, sometimes naked, oftener feathered. In size the 

 Hummers average the least of all birds, the giants among them alone reaching a length of 6 or 

 7 inches, the pygmies being under 3 inches; the usual stature is 3 or 4 inches, lu a few the 

 coloration is plain, or even sombre; most have glittering iridescent tints — "the most gor- 

 geously brilliant metallic hues known among created things." The sexes are usually unlike 

 in color. 



The chief anatomical peculiarity is the structure of the tongue, which somewhat resembles 

 that of woodpeckers, in being protrusible or capable of being thrust far out of the beak by » 

 muscular mechanism connected with the long horns bf the hyoid or tongue-bone, which curve 

 lip around the back of the skull. The tongue is in effect a double-baiTelled tube, supposed to 

 be used to suck the sweets of flowers. The character of the sternum and wing-bones has been 

 already mentioned. How perfectly the feet iirc fitted for grasping and perching may be inferred 



