BIRDS OF NORTH AND MIDDLE AMERICA. 5381 
Thaluronia (misprint?) Gray, Gen. Birds, i, App., 1849, 5, in text. 
Glaucopes ‘‘Less[on]” Gray, Gen. Birds, i, Dec., 1848, 108, in text. (Type, 
Trochilus glaucopis Gmelin.) 
Glaucopis Burmeister, Syst. Ueb. Th. Bras., ii, 1856, 333. (Type, Trochilus 
glaucopis Gmelin.) 
Medium-sized Trochilide (length about 95-115 mm. in adult males, 
90-98 in adult females) with bill about as long as head, straight or 
slightly decurved, the terminal portion of maxillary tomium serrated ; 
nasal operculum mostly concealed, tail forked or (in females) emar- 
ginate, with relatively broad lateral rectrices, the adult males with 
under parts bright metallic green or (often) with under parts of body 
violet and tail uniform blue-black or violet-black, the adult females 
with under parts pale gray (under parts of body sometimes metallic 
greenish), and lateral rectrices tipped with pale grayish (sometimes 
greenish or grayish basally). 
Bill about as long as head, straight or slightly decurved, terete or 
slightly broader than deep basally; culmen broadly rounded, but 
basally contracted into a distinct narrow ridge; terminal portion of 
maxillary tomium serrated; mandible with a distinct lateral groove or 
sulcus, the maxilla with indication of the same. Nasal operculum 
rather narrow, mostly covered by frontal feathering, which forms 
distinct antiz on each side of mesorhinium, extending forward at 
least to middle of nasal operculum. Tarsus completely clothed with 
short feathers; middle and inner toes about equal in length, the 
outer slightly shorter, the hallux shorter than outer toe. Wing about 
three times as long as culmen, the outermost primary longest. Tail 
nearly as long as wing to less than two-thirds as long, forked in adult 
males, emarginate or slightly forked in females, the lateral rectrices 
relatively broad, all rather rigid, with rounded tip. 
Coloration.—Adult males metallic green or green with violet or 
black (sometimes both) above, the forehead and crown sometimes 
brilliantly metallic green or violet; tail uniform black, blue-black 
or violet-black; chin and throat, sometimes chest also—in some 
species whole or most of under parts—very bright metallic green, 
the under parts of body usually rich metallic violet, in abrupt con- 
trast. Adult females metallic green or bronze-green above, pale 
gray beneath, the lateral rectrices tipped with pale gray and some- 
times gray or greenish basally. 
Range.—Western Mexico to Cayenne, southeastern Brazil, Bolivia, 
and Peru. (About sixteen species.) 
KEY TO THE SPECIES AND SUBSPECIES OF THALURANIA. 
a. Throat and chest bright metallic green; under parts of body metallic green, violet- 
blue, or blackish. (Adult males.) 
b. Lesser wing-coverts and anterior scapular region (sometimes upper back also) 
violet or violet-blue; tail dark steel blue or dark violaceous-blue. 
