BIRDS OF NORTH AND MIDDLE AMERICA. 369 



Circea (not of Mertens, 1835) Gould, Monogr. Trocli., pt. xiii, May 1, 1857; 1861, 



168. (Type, Cynanthus latirostris Swaiiipon.) 

 lache Elliot, Classif. and Synop. Troch., March, 1879, 234. (Type, Cynanthus 



latirostris Swainson.) 



Rather small Trochilidse (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 

 imfeathered (except at extreme base) and frontal feathering forming 

 a transverse line; tail distinctly forked (sometnnes 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 ami 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 7nales.) 



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. 



c. 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 KlpKTi, Circe." (Gould.) 

 81255°— Bull. 50—11 24 



