BIRDS OF NORTH AND MIDDLE AMERICA. 369 
Circe @ (not of Mertens, 1835) GouLp, Monogr. Troch., pt. xili, May 1, 1857; 1861, 
168. (Type, Cynanthus latirostris Swainson.) 
ache Expror, Classif. and Synop. Troch., Match, 1879, 234. (Type, Cynanthus 
latirostris Swainson.) 
Rather small Trochilide (length about 80-90 mm.) with bill 
decidedly longer than head, very faintly decurved, broader than 
deep, broad and depressed basally, with the broad nasal operculi 
unfeathered (except at extreme base) and frontal feathering forming 
a transverse line; tail distinctly forked (sometimes for more than 
one-third its length in adult males), the middle rectrices broad 
and all rounded terminally; adult males metallic green below, some- 
times with chin or chin and throat blue, the tail blue-black with 
deep gray tips to middle rectrices, adult females brownish gray 
below, with gray tips to lateral rectrices. 
Bill decidedly longer than head, broader than deep, broad and 
depressed basally, very faintly decurved; culmen broadly rounded 
but contracted to a narrow ridge at base; tomia smooth; maxilla and 
mandible (especially the latter) each with a distinct narrow median 
groove. Nasal operculum broad, tumid, completely nude, the frontal 
feathering forming a transverse line across base of forehead. Tarsus 
naked except upper portion, slender; anterior toes about equal in 
length, the hallux slightly shorter; all the toes slender, with claws 
relatively small. Wing about two and a half to three times as long 
as bill, with outermost primary longest. Tail nearly to quite half as 
long as wing, deeply emaginate or forked in adult males, less deeply 
emarginate in females, the middle rectrices very broad, the lateral 
ones narrower, all rounded terminally. 
Coloration. Above rather dull metallic bronze-green, the forehead 
more brilliant green or blue; adult males with tail blue-black, the 
middle rectrices tipped with brownish gray, the under parts metallic 
green, usually passing into blue on chin or chin and throat; lumbar and 
femoral tufts white; adult female with middle rectrices metallic 
greenish, lateral (but not middle) rectrices tipped with gray, and 
under parts brownish gray. 
Range.—Mexico and adjacent portions of Arizona and New Mexico. 
(Three species.) 
KEY TO THE SPECIES OF CYNANTHUS. 
a. Under parts metallic green (with or without blue on throat); rectrices blue-black, 
the middle ones tipped with brownish gray. (Adult males.) 
b. Tail forked for not more than one-fourth its total length; wing, 49-54.5; exposed 
culmen, 18.5-22; forehead and crown not brilliant metallic green or blue. 
ce. Larger, with longer bill (wing averaging 52.5, culmen 21); back and rump 
more decidedly green; chin and throat greenish blue or decidedly bluish 
a “Ex Képxn, Circe.”? (Gould.) 
81255°— Bull. 50—11——24 : 
