306 NORTH AMERICAN BIRDS. 



grayish, at tip and base, blue-black in 



middle portion Chlorostilbon} 



■p. Middle tail-feathers bronzy ; females and young 

 males without grayish base or tip to outer 



tail-feathers Sporadinus} 



A". Tail less than three-fourths as long as wing, 

 variously shaped, but never forked for more 

 than one-fourth its length ; adult males vari- 

 ously colored, but never entirely green, 

 beneath. 

 ■)}. Lower parts pure white, the sides sometimes 

 green, or spotted with green ; sexes 

 alike. 

 /. Exposed culmen decidedly more than 

 half as long as tail; top of head 

 usually metallic blue or violet. 



Uranomitra? 



f. Exposed culmen not more than half as 



long as tail ; top of head never blue 



or violet Agyrtria* 



f. Lower parts never pure white. 



/. Tail bright bluish green or greenish blue, 

 crossed near end by a broad band of 

 blue-black. 



Breast and sides of head deep blue ; 

 throat brilliant green, the centre 

 of each feather darker; sexes 

 alike ; wing 2.60-2.80. 



Petasophora} 

 f. Tail not bluish green, etc. 



k\ Feathering of forehead extended 

 forward as far as anterior end 

 of nostrils, and partly or en- 

 tirely covering the scale over 

 nostrils. 



1 Chlorostilbon Gould, Mon. Troch. pt. v. 1853. Type, Trochilus pucherani BouRC. & Muls. (Three species 

 in Mexico, one in Porto Rico, and about six in South America.) 



2 Sporadinm Bonap., Rev. et Mag. Zool. 1854, 255. Type, Trochilus riceordi Gerv. (One species in Haiti, 

 one in Cuba and Bahamas, and apparently one peculiar to Bahamas.) 



3 Uranomitra Reich., Aufz. der Colib. 1853, 10. Type, Trochilus francim BouRC. & MuLS. (Four species 

 in Mexico, one in Honduras, one in Colombia, and one in Peru.) 



* Agyrtria Reich., Troch. Enum. 1855, 7. Type, Trochilus hrevirostris Less. (Two Mexican and numerous 

 South American species; some of the latter with lower parts mostly green; one of the former with buffy or 

 rufous belly and flanks.) 



5 Petasophora Gray., List Gen. B. 1840, 13. Type, Trochilus scrrirostris Vieill. (One species in Mexico 

 and Guatemala, several in Central and South America.) 



