Henshaw on Selasphorus alleni. 
11 
crossed by numerous (seven or eight, the number rather indefinite, how- 
ever) bars of black ; these bars becoming broken towards the ends, and 
gradually obsolete at the bases of the feathers ; the ground-color occasion- 
ally paler along the posterior edge of the blackish bar. Whole side of the 
head and entire lower parts white, the sides faintly tinged with buff. A 
distinct dusky stripe along upper edge of auriculars, below the very con- 
spicuous and continuous white superciliary stripe. Bill and feet plum- 
beous-dusky. Wing, 2.30-2.45; tail, 2.30-2.45; bill, from nostril, 
.45 - .48 ; culmen, .75 - .78 ; tarsus, .80 ; middle toe, .50. 
Habitat. Tres Marias Islands, off the western coast of Mexico. 
Types . 37,329, $ (Jan. 1865), 50,817, and 50,818 (U. S. Nat. Mus. 
Catal.), Tres Marias ; Col. A. J. Grayson. 
The principal characteristics of this form and the typical one may be 
contrasted as follows : — 
a. felix. Throat bordered along each side by a wide and conspicuous 
stripe of black ; whole sides of neck and also auriculars distinctly streaked 
with black ; entire lower parts, except throat, buff, deepest along sides. 
Wing, 2.10-2.35 ; tail, 2.25-2.35 ; bill, from nosjril, .39 -.42 ; tarsus, 
.80 -.90 ; middle toe, .50-52.* Hob., mainland of Western Mexico, from 
Mazatlan to Oaxaca. 
/3. lawrencii. Black markings of cheeks, etc., usually entirely absent, 
very rarely barely indicated ; lower parts, except sides, pure white. Wing, 
2.30 - 2.45 ; tail, 2.30 - 2.45 ; bill, from nostril, .45 - .48 ; tarsus, .80 ; 
middle toe, .50. t Hah., Tres Marias Islands, Western Mexico. 
ADDITIONAL REMARKS ON SELASPHORUS ALLENI. 
BY H. W. HENSHAW. 
In his remarks on Selasphorus alleni, in the October number of 
the Bulletin, Mr. D. G. Elliot attempts to prove that in selecting this, 
the Green-backed, J or, as he calls it, the Californian form, for naming, 
I committed an error, this, according to him, being the bird described 
by Gmelin as the Trochilus rufus, and hence, as he claims, it was 
* Five specimens measured, all from Mazatlan. 
+ Three specimens measured. 
+ In this article, by the Green-backed Hummer will be understood the 
recently recognized form from California ; the Rufous-backed bird being the 
old and better known form from Mexico and the West Coast generally. The 
coloring of the adult males renders these names sufficiently appropriate. 
