340 REPORT OF NATIONAL MUSEUM, 1890. 



nosis tbau the above. The typical species are easily recognized, so 

 far as the males are concerned, by the narrow and pointed onter prim- 

 ary, all of the northern species possessing this character, while one 

 of the southern species (8. scintilla) does also; while as to coloration? 

 the males of all are characterized by a greater or less amount of rufous, 

 longitudinally disposed, on at least some of the tail-feathers. The tail 

 is more or less graduated or wedge-shaped, except in 8. platycercus, in 

 which six middle feathers are about equal in length, the two outer pairs, 

 successively, decidedly shorter. All have a more or less brilliant me- 

 tallic gorget, which in all of the species except S. platycercus has the 

 postero-lateral feathers elongated into a conspicuous "rufi." Only 

 S.floresii has the top of the head brilliantly metallic (the same color 

 as the throat), thus showing an affinity to the genus or subgenus Calypte^ 

 which, however, has an emarginate and differently colored tail and 

 very differently shaped outer i)rimary. 



It is very difficult to recognize generic or subgeueric characters in 

 the females; but their more graduated tails, with a considerable quan 

 tity of rufous on the basal portion of at least three of the rectrices 

 willdistinguish them from the females of any other North American Hum 

 raing Birds, except Stellula calliope, which has the rufous much more re 

 stricted as well as paler and duller, and the six middle feathers of some 

 what spatulate or paudurate form ; and from those of any Mexican 

 genera except Atthis, Doricha, and Calothorax, which, except the first, 

 differ in having a curved bill and short middle tail-feathers. 



The female of Atthis heloi sa is essentially similar to that of some spe- 

 cies of Selasphorus in the coloration of the tail, but the latter is double- 

 rounded, and the outer primary is much broader. 



The known species of Selasphorus may be distinguished as follows: 



a'. Top of the head brilliaat metallic red, like the gorget. Hab. : Western Mexico ; 

 San Francisco, Cal. ? 



S. floresii GOVLD. FloresVs Eumviing Bird. (Page 341.) 

 a'. Top of the head greenish, totally different from the color of the gorget. 



bK Middle tail-feathers rufous, with a median streak or stripe of black; gorget 

 brilliaat fire-red or metallic scarlet, 

 c'. Upper parts (except top of head) rufous, sometimes glossed with green on the 

 back. Hab. : Western North America .south to Mexico. 



S. rtifiis Gmel. Rufous Humming Bird. (Page 343.) 



c^. Upper parts mainly metallic green. 



d'. Larger (like {S. rufus), with upper tail- coverts wholly rufous. Hab. : British 



Columbia to Arizona. S. alleuiRKNSH. J llcn^s Humming Bird, (Page347.) 



d'. Smaller (wing only 1.30, culmen less than .50), with upper tail-coverts partly 



green. Hab.: Costa Rica and Veragua. 



S. scintilla Gould. Sparkling Humming Bird.* 

 6^. Middle tail-feathers merely edged with rufous or (in S.plaiijcercus) with no ru- 

 fous whatever. 



* Trochilus {Selasphorus) scintilla Gould, P. Z. S., 1850, 162. 



