136 



U. S. P K. R. KXP AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



In this species the metallic scales of the throat exteud about as far back as in the Trochilus 

 coluhris. The tail feathers are all broad ; the outer one is rounded at the end and widens from 

 the base ; the next succeeding feathers have the edges parallel at the base, and the tips rather 

 acute. The innermost feather is a little shorter than the longest (by about .05 of an inch) ; 

 the outermost about .15 shorter ; and the tail is thus moderately graduated and slightly 

 emarginate. 



The general appearance of this bird is not unlike that of the common ruby-throated T. 

 coluhris, although the two are distinguishable by generic peculiarities. 8. platycercus is the 

 larger bird, although the bill, if anything, is a little smaller. The graduated tail, with the 

 broad, rounded, almost oblanceolate outer feather, is, however, in strong contrast to the deeply 

 forked tail, with the acutely tapering outer tail feather of T. coluhris. 



A remarkable peculiarity in this species (shared by C. rufus) is seen in the outermost primary. 

 This is narrower and more linear than in most of our other species, as well as straighter or less 

 falcate. The terminal half inch is abruptly attenuated and linear, so as not to exceed .03 of an 

 inch in width. 



The green of the throat in this species is purer and less mixed with golden than in the T. 

 coluhris. The throat has a violet jiurple reflection instead of a fiery copper red. The crissum 

 and breast are of a purer white. All the tail feathers, except the innermost, (which is like the 

 back,) have a cinnamon edging on the inner edge, except at the extreme tip ; this is seen on 

 both webs of all, except the first, where it is confined to the inner. This border is very 

 conspicuous on the outer edge of the fourth feather. 



I have no female of this species before me, but a specimen in the collection of the Philadelphia 

 Academy, supposed to belong here, has no rufous on the tail. 



In comparing specimens in the Philadelphia Academy, as well as that from El Paso, with 

 Gould's figure, this is seen to indicate a much larger bird, (nearly 4^ inches long,) with longer 

 tail and broader feathers, the external more pointed. Whether this would indicate the fact of 

 a confounding of two species I am unprepared to say. His figure of the female shows very 

 distinctly a rufous margin to the tail feathers. 



For the determination of this species, now for the first time introduced into the fauna of the 

 United States, I am indebted to Mr. John Gould, who identified it when examining the speci- 

 mens of Humming Birds preserved in the Smithsonian Institution. 



List of specimens. 



Locality. 



When collected. 



El Paso, Texas . 

 Mexico 



1851 



Whence obtained. 



Mnj. W. H. Emory . 

 Verreaux 



Original 

 No. 



Collected by- 



J. H. Clark. 



.34873 



ATTIIIS, Reichenbach. 



Jllthis, Reichenbach, Cab. Journal fiir Orn. Extralioft fiir 1853, 1854. App. B. (named only.) 



I am not sure that tlie diagnosis given of tliis genus is that of its founder, but it will answer 

 to separate a well marked form from the other North American species. It is most like Selas- 

 plu/ru8, and its species have usually been placed in tliis genus ; it difi'ers, however, in the 



