438 NORTH AMERICAN BIRDS. 



luuiJretl and thirty genera, only two subfamilies have heen recognized, as 

 follows : — 



PhEethornithincB. Anterior toes connected at the base. No metallic lus- 

 tre to till/ dull plumage. 



Trochilinae. Anterior toes not connected at the btise. Plumage brilliant, 

 with more or less of metallic lustre, at least in the males. 



The first-mentionetl subfamily embraces five genera, and about fifty 

 species, none of which are found iu the United States. The TrocJiilinw 

 count nearly four hundred species and one hundred and twenty-five genera, 

 and in the absence of any successful attempt to arrange them in subordinate 

 groups, the difficulties of determination on tJie part of the tyro may readily 

 be imagined. 



Of the seven genera accredited to North America, with their ten species, 

 we cannot pretend to do more than present an artificial analysis, which may 

 serve to define them as compared with each other, but bear little reference 

 to the family as a whole. The characters are selected partly from the shape 

 of tail and partly from color. 



Co.M.MON Cn.\RACTERS. All the North American Trochilidce have metallic green 

 backs, excepting Selasphorus ru/us, this color extending over the top of head, 

 except in Calypie (metallic red and violet), and Heliopwdica (bluish-black). The 

 latter alone has a white stripe through the eye. Aithis heloisce alone has the tail 

 tipped with white in the male. Females of all the species except Heliopcedica 

 have tail tipped with white; all have it rounded. All females lack the metallic 

 throat. The males of the several genera belonging to North America may be 

 distinguished as follows : — 



I. Bill covered with feathers hetween nostrils. 



A. Top of head green. 



Feathers of throat not elongated. 



Tail rounded or slightly emarginated, the feathers broad, rounded, and 

 metallic rufous-purple, or greenish-blue. Wing more than 2.50 . Lampornis. 

 Tail more or less forked ; feathers pointed, narrow, and without rufous 



or blue. Wing much less than 2.00 IVochilus. 



Throat-feathers elongated laterally into a kind of ruff. Tail-feathers edged 

 or banded with cinnamon at base. 



Tail cuneate, the outer primary attenuated at end. Innermost tail- 

 feather green above. 



Tail dusky at end Selaspho7-us. 



Tail tipped with white Atthis. 



Tail nearly even, and emarginated. Outer primary not attenuated at 

 end. Innermost tail-feather brown above Stellula. 



B. Top of head metallic red or violet. 



Metallic feathers of side of throat much elongated Calypte. 



II. Bill hare of feathers hetween the nostrils. 

 C Top of head bluish-black ; a white line through eye. 



Metallic feathers of side of throat not elongated. 



Tail nearly even, and sliglitly emarginated. Lateral feathers very 

 broad and obtuse at end Heliopaidica. 



