340 REPORT OF NATIONAL MUSEUM, 1890. 



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

 far as the males are concerned, by the narrow and pointed outer 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 "rufl."" Only 

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

 as the throat), thus showing an affinity to the genus orsubgenus Galypte, 

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

 very differently shaped outer primary. 



It is very difficult to recognize generic or subgeneric 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, 

 will distinguish them from the females of any other North American Hum- 

 ming 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 pandurate 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 leathers. 



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: 



MALES. 



a 1 . Top of the head brilliant metallic red, like the gorget. Hdb. : Western Mexico ; 

 San Francisco, Cal. f 



S. floresii GOULD. FloresVs Humming Bird. (Page 341.) 

 a 1 . Top of the head greenish, totally different from the color of the gorget. 



6 1 . Middie tail-feathers rufous, with a median streak or stripe of black; gorget 



brilliant fire-red or metallic scarlet. 



c 1 . Upper parts (except top of head) rufous, sometimes glossed with green on the 

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



S. rufus GMEL. Rufous Summing Bird. (Page 343.) 

 c 2 . Upper parts mainly metallic green. 



d 1 . Larger (like (S. rufus), with upper tail- coverts wholly rufous. Hal. : British 

 Columbia to Arizona. S. alleni HENSH. Allen's Humming Bird. (Page347.) 

 d 2 . Smaller (wing only 1.30, culmen less than .50), with upper tail-coverts partly 

 green. Hob. : Costa Rica and Veragua. 



S. scintilla GOULD. Sparkling Humming Bird.* 



6 2 . Middle tail-feathers merely edged with rnfous or (in S.platycercus} with no ru- 



fous whatever. 



* Trochilus (Selasphorus) scintilla GOULD, P. Z. S., 1850, 162. 



