ERIOCNEMIS DERBIANUS. 



Derby's Puff-leg*. 



Trochilus Derbyi, De Latt. et Bourc. Rev. Zool. 1846, p. 306. 

 Eriopus Derbyi, Gould in Proc. of Zool. Soc, part xv. p. 17. 



derbyi, Bonap. Consp. Gen. Av., p. 80, Eriopus, sp. 7. 



Eriocnemys derbyanus, Bonap. Rev. et Mag. de Zool. 1854, p. 252. 

 Threptia Derbyi, Reiclienb. Aufz. der Colibris, p. 9. 



That the study of the great family of the Trochilidae, when all the species are known and the areas of 

 habitat enjoyed by each are ascertained, will tend to throw some light on what may or may not be termed 

 species, I think there can be little doubt. The various members of the genera Oreotrochilus, Oocypogon and 

 Ramphomieron live at elevations varying from 10,000 to 16,000 feet, and are confined to such limited areas, 

 that a single cone like that of Chimborazo or Cotopaxi is the extent of their range ; on the other hand, 

 many of the extinct volcanos have species peculiar to the shrubby regions on their inner sides. Surely 

 such facts as these are worthy of a greater share of the attention of philosophers than has hitherto been 

 devoted to them. The bird figured on the accompanying Plate serves well to illustrate the foregoing 

 passage, for up to the present time it is only known to inhabit the extinct volcano of Purace, where 

 it was discovered by the late M. De Lattre during his travels in the little-trodden countries of New 

 Grenada. 



The Eriocnemis Derbianm is a species which differs very remarkably from every other member of the 

 genus, both in the coal-black colouring of its feathered legs and in the brilliant metallic golden green of 

 its upper and under tail-coverts. No other traveller but De Lattre has, I believe, obtained examples of this 

 bird; by him, however, at least forty of both sexes were procured, all of which realized very high prices. 

 These examples were so precisely alike both in colour and markings that they scarcely presented a shade 

 of difference. 



In the year 1846, MM. De Lattre and Bourcier named this species in honour of the late Earl of Derby, as 

 a just tribute of respect to that distinguished nobleman, whose life was certainly not rendered less happy by 

 his study of the branch of natural science to which he was so much attached. 



The male has awash of green on the forehead; the head, all the upper surface and wing-coverts of a 

 golden bronzy hue ; all the under surface shining golden green ; wings purplish brown ; upper and under 

 tail-coverts brilliant metallic green ; tail, feathers of the tarsi, and bill black. 



The female has a wash of green on the forehead ; all the upper surface golden bronze ; under surface 

 similar in hue, but lighter and more brilliant ; upper and under tail-coverts metallic golden green ; wings 

 purplish brown ; tail black ; feathers of the tarsi black towards the knee and greyish white near the feet. 



The Plate represents two males and a female of the size of life on the Mavillaria leptosepala. 



