14 
Henshaw on Selasphorus alleni. 
not have been the one with the bright green hack. “ Trochilus 
rufus snbtus exalbidus ” points at once to the Rufous-backed form. 
The other bird with the small amount of rufous below would 
scarcely have suggested this name. Referring to Swainson’s ac- 
count, which was, as Mr. Elliot remarks, in all probability based upon 
one of Gmelin’s original specimens, possibly his type, we find his 
description beginning thus, “ General tint of the upper plumage 
rufous or cinnamon, which covers the head, ears, neck, back, 
rump, upper tail-coverts, and margins of the tail-feathers ” 
This applies perfectly to the Rufous-backed form, but in no wise 
meets the necessities of the other bird. For while color is not the 
most desirable test, and may often prove unreliable, yet in the case 
of the males of these tw T o birds the variation in color, while consid- 
erable, as pointed out in my former article, is never sufficient to 
obliterate their specific distinctness. They may be invariably told 
by the color of the back alone. 
Mr. Elliot appears to have overlooked much of Swainson’s article. 
For in his remarks that author states, after indicating that he has 
before him one of Gmelin’s original specimens as correctly quoted 
by Mr. Elliot, “We are likewise able to vouch for its geographic 
range to the southward as far as the table-land of Mexico, near Real 
del Monte ; specimens from that part having been obligingly sent 
us for examination ” Thus Swainson vouches for the identity 
of Gmelin’s original specimen, perhaps type, with the Mexican 
form, which is, as Mr. Elliot says, the Rufous-backed bird. Could 
stronger proof be asked 1 
Mr. Elliot’s discrimination in the color of the ruffs of the two 
species I have not been able to verify. The differences he appears 
to have found in his specimens I am sure, after having ex- 
amined numerous individuals, are not constant, and hence are 
of no use as diagnostic features. Mr. Elliot says, “ I do not 
think that the females have any metallic feathers on the throat.” 
In this he is mistaken. Adult females invariably have a metallic 
patch on the median line of the throat. The young males are very 
differently marked, and have the metallic feathers, which become 
brownish towards the chin, distributed quite evenly over the throat, 
the space occupied by them often indicating the extent of the ruff 
of the following year. The young females alone have the throat 
almost immaculate, or faintly flecked with brown. 
Range. We have no proof at the present time showing that the 
