134 U. S. p. R. R. EXP. AND SURVEYS — ZOOLOGY GENERAL REPORT. 



Tail strongly cuneate, the middle feather much longest and very broad ; the outer very 

 narrow, one-fifth the width of the middle. Body chiefly cinnamon colored ; throat feathers a 

 coppery red ; top of head, and an occasional gloss on the hack, green ;S'. rufus. 



Tail rounded ; the middle feather a little shorter than the next one ; the outer rather hroad, 

 more than one-half the width of the middle one. Ahove, and on the sides below, green. 

 Throat feathers purple. Edges of some tail feathers cinnamon brown S. plalycercus. 



SELASPHORUS EUFUS, Swainson. 



Red-backed Humming Bird. 



Trochibts rvfus, Gmelin, Syst. Nat. I, 1788, 497.— Aud. Cm. Biog. IV, 1838, 555 ; pi. 372. 

 Selasphorus rufus, Swainson, F. Eor. Am. II, 1831, 324.— Ib. Aud. Birds Am. IV, 1842, 200 ; pi. 254. 

 .' Trochilus ruber, L.— Orn, I, 1788, 499. (Fide Bonaparte.) 

 Trochilus collaris. Lath. (Bonaparte.) 

 Trochilus silkensis, Rathke. (Bonapaite.) 

 Ornysmia sasin, Lesson. (Bonaparte.) 



Sp. Ch. — Tail strongly cuneate and wedge-shaped. Upper parts, lower tail coverts, and breast cinnamon. A trace of 

 metallic green on the crown, which sometimes extends over the back ; never on the belly. Throat coppery red, with a well 

 developed ruff of the same ; below this a white collar. Tail feathers cinnamon, edged or streaked at the end with purplish brown. 



Female with the rufous of the back covered or replaced with green ; less cinnamon on the breast. Traces only of metallic 

 feathers on the throat. Tail rufous, banded with black and tipped with white ; middle feathers glossed with green at the end. 

 Tail still cuneate. Length of male, 3.50 ; wing, 1.55 ; tail, 1.30. 



Hab. — West coast of North America, and across from Gulf of California to the Upper Rio Grande Valley. 



This species is about the size of the common ruby- throated humming bird, which it resembles 

 also in many respects. The bill is rather narrower. The wings are long and falcate ; the two 

 first primaries elongated and acutely lanceolate, but not attenuated as abruptly as in platycercus; 

 the third is also acute. In most of the other species the first quill is much more linear than the 

 second, and less acute than in this. 



The tail is strongly cuneate ; the outer feather .40 of an inch shorter than the middle, which 

 projects .14 of an inch beyond the rest. The outer feather is very narrow, not exceeding .11 of 

 an inch in width ; the rest widen and lengthen rapidly to the central one, which is very broad, 

 (.35 of an inch ;) the central feathers are all ovate acuminate. 



In the female the primaries are less acutely falcate than in the male. The tail also, though 

 cuneate, is less acutely so than in the male ; the outer feathers broader and less acutely pointed. 

 In the male, in its highest plumage, the entire upper parts, excepting the crown and the wing, 

 (but including the tail,) the sides of the body under the wings, and a broa-l band across the 

 breast and abdomen, with the lower wing coverts, cinnamon brown, rather paler beneath. The 

 crown is obscurely golden gieen, not well defined. Tlie entire throat, including a short rufi"on 

 the side of the neck, (about .40 of an inch long,) is metallic red, of the same shade as in the 

 ruby-throat, although with brassy reflections in some lights. The sides of the neck beneath the 

 rufi', the upper part of the breast, the anal region, and a small spot behind the eye are dull 

 white. The wings are violaceous brown, their coverts metallic green. The tail feathers are 

 cinnamon, with the outer webs near the tips violaceous brown ; this gradually becoming central 

 instead of on the outer side. 



In some specimens, probably immature, the back shows spots of metallic green, while in 

 others (as 6059) it is entirely covered with this color, except on the tail. 



The female is entirely of a metallic green above, with, however, more or less of a cinnamon 



