252 Birds of Colorado 
b. Tail-feathers rufous on basal half. 
al Outer tail-feathers about -25 across, very little if any rufous 
on the flanks. S. platycercus, 2 p. 253. 
b! Outer tail-feathers narrower, about -12 across; flanks and 
under tail-coverts washed withrufous. S. rufus, 2 p. 255. 
Genus ARCHITROCHILUS. 
Bill long, slender and black ; nostrils concealed ; wing with the outer 
primary incurved and scimitar-shaped ; tail forked in the male, the 
feathers lanceolate and pointed, but not specially narrowed; in the 
female rounded and white-tipped ; male with a metallic gorget, pro- 
duced and elongated at the corners; no rufous about the plumage. 
Two species in the United States; the Ruby-throat of the east does 
not normally come further west than eastern Nebraska and Kansas, 
but may possibly stray to Colorado. 
Black-chinned Humming-bird. Architrochilus alexandri. 
A.O.U. Checklist no 429—Colorado Records—Morrison 86, p. 153; 
88, p. 107; 89, p. 146; Bendire 92, p. 198; Cooke 97, pp. 86, 208. 
Description.—Male—Above golden-green; wings dusky purplish, 
below grey, greenish at sides ; throat velvety-black becoming iridescent 
violet posteriorly ; tail forked about -1; tail-feathers pointed. Length 
3-25; wing 1-65; tail 1-1; culmen -7. 
The female has no gorget, the throat sometimes with dusky spots ; 
tail rounded, all but the central feathers dusky purplish with terminal 
bands of white; wing 1-9. 
Distribution.—Western North America from southern British 
Columbia to western Texas and Sonora, wintering to southern Mexico. 
The Black-chinned Humming-bird is confined to the south-west and 
western portions of Colorado. Morrison found it fairly common and 
breeding in La Plata co. about Fort Lewis; a fine male was taken 
near Glenwood Springs in 1898 by William Cross. These are the only 
definite records for the State. 
Habits.—Morrison states he was shown a nest con- 
taining three eggs; this is unusual, as Humming-birds 
almost invariably lay but two eggs. 
Genus SELASPHORUS. 
Nostrils concealed; wing with the outer or two outer primaries 
strongly attenuated and bowed in the male, less so in the female; tail 
rounded or graduated, not forked; male with a gorget not produced 
