154 Mr. D. G. Elliot on the Trochilida. 



cier redescribed it as T. chrysogaster, from Cartagena in 

 Columbia. Mr. Gould had these two types in his hands when 

 writing his monograph of the family, and there states that, 

 " of one thing I am certain, namely that the amjustipennis 

 of Eraser, and the chrysogaster of Bourcier, are one and the 

 same bird ; for I have the types of both now before me, and 

 they do not differ in the slightest degree." And in this deci- 

 sion he was undoubtedly correct. In 1860 Mr. Gould de- 

 scribes another specimen of this species, from Ecuador, as C. 

 melanorhynchus ; but in his ' Introduction,^ issued in the fol- 

 lowing year, he states that he believes this to be the same as 

 chrysogaster, Bourcier. Just before this, however, he reverses 

 his decision as regards angustipennis , Eraser, and chrysogaster, 

 Bourc, being identical, and states he then believes them to 

 be distinct, although unfortunately he does not give the reason 

 which induced him to undertake this change of base. In 

 1860 Mr. Lawrence described a specimen from Panama as C. 

 assimilis (compared with melanorhynchus, Gould, and stated to 

 be smaller) ; and in 1872 Mr. Gould described one from Citado, 

 in Ecuador, as C. pumilus. 



These appear to be the prominent names given to this 

 species ; and all of them have been more or less employed by 

 ornithologists to designate some one specimen or another of 

 the green Humming-birds with a black bill and tail, as they 

 were able to interpret the various descriptions given by dif- 

 ferent authors. One point that appears to have had the most 

 influence upon describers is the size of their examples, either 

 in the length of the bill (generally deemed very important), 

 or length of wing, or tail, and sometimes the amount oifork 

 exhibited by the feathers of the latter. Probably the difter- 

 ences have often been the result of age, as regards the bill, or 

 the plumage not having arrived at a complete state, as re- 

 gards the wing and tail, more especially the latter. With 

 but a limited number of specimens to judge from, and (as 

 would be the natural result) the unconsciousness of the vari- 

 ation shown among individuals in measurements equally with 

 the colouring of their plumage, a naturalist would be most 

 apt to consider that his examples belonged to more than one 



