366 KEPORT OF NATIONAL MUSEUM, 1890. 



staii I and therefore not diagnostic, thus reducing the differential char- 

 acters of the two forms to the coloration of the under parts alone, A. 

 yucatanensis having the breast, belly, sides, flanks, and under tail- 

 coverts much deeper in color, or a clear deep cinnamon-rufous, the 

 absence of any distinct wash of bronze-green on the sides of the breast 

 rendering the contrast between the brilliant green of the throat and 

 chest and the cinnamon-rufous color which follows it much more abrupt 

 and conspicuous. 



The Buff-bellied Humming Bird, the plainest species of the family 

 that has hitherto been added to our fauna, was first obtained within our 

 limits by Dr. J. C. Merrill, U. S. Army, at Fort Brown, Texas, in 1876. 

 It was there an abundant summer visitor, being particularly numerous 

 on the military reservation. It seemed to be perfectly at home among 

 the dense tangled thickets, darting rapidly among the bushes and 

 creeping vines, and was so active that specimens were obtained with 

 difficulty. It was rather a noisy bird, its shrill cries usually first attract- 

 ing attention to its presence.* 



Mr. George B. Sennett met with it at the same place the following 

 year, but only obtained one specimen, which was shot while hovering 

 over wild flowers near the ground, among cacti and low bushes, t 



I am unable to add anything further regarding its habits. 



Rieffer's Humming Bird. Amazilia fuscicaudata (Eraser). 

 (Plate xliii.) 



Trochilus fuscicaudatus Fras., P. Z. S., 1840, 17 (Ecuador). 



Amazilia fuscicaudata Merrill and Ridgw. , Pr. U. S. Nat. Mus., i, Oct., 1878, 147 

 (Fort Brown, Texas). 

 Trochilus riefferi Bourc, Ann. Sci. Phys. et Nat. Lyon, 1843, 45. 



Amazilia riefferi Reich., Av. Syst. Nat., 1849, pi. 39. — Gould, Mon. Troch., pt. 



xix, 1860, pi. 14 ; vol. v, 1861, pi. 311. 

 Pyrrhophcena riefferi Cab. and Heine, Mus. Hein., in, 1860, 36. — Merrill, Bull. 

 Nutt. Orn. CI., I, Nov., 1876, 88 (Fort Brown, Texas). 

 Rieffer's Ainazili (Gould ). 

 Dusky-tailed Hummiug Bird (Coues). 

 L'Ariane de Rieffer (Mulsant and Verreaux). 



Range. — The whole of Central America and eastern Mexico ; north 

 to the lower Rio Grande Valley in Texas ; south to Ecuador. 



Sp. Char. — Lores rusty ; breast and belly pale brownish gray ; upper 

 parts metallic bronze-green, darker on top of head, more bronzy or 

 golden on rump ; tail deep chestnut, including middle feathers, the 

 feathers tipped and margined more or less extensively with bronze or 

 purplish ; throat and chest brilliant metallic yellowish green, the 

 feathers pale grayish beneath the surface, showing wherever the 

 feathers are disarranged ; sides and flanks bronze-green ; under tail- 



*Pr. U. S. Nat. Mus., Vol. I, 1879, pp. 149, 150. 



t Bull. U. S. Geol. & Geog. Surv. Terr., Vol. iv, No. 1, p. 36. 



