CYNANTHUS SMARAGDICAUDUS, Oouid. 



Green-tailed Sylph, 



Trochilus [Lesbia) smaragdinus, Gould in Proc. of Zool. Soc, Part XIV. p. 85. 

 Trochilus Mocoa, De Latt. et Bourc. in Rev. Zool., 1846, p. 311. 



Mellisuga smaragdifiis, Gray and Mitch. Gen. of Birds, vol. i. p. 113, MeUisuga, sp. 52 

 CynantMis mocoa, Bonap. Consp. Gen. Av,, p, 81, Cynanthus, sp. 3. 



In general structure this beautiful species is most closely allied to the Blue-tailed Sylph {Cynantlius 

 cya7iurus) ; it is, however, of rather smaller size, and may at all times be distinguished by its resplendent 

 metallic green tail : unfortunately nothing whatever is known of its habits and economy, but they are 

 doubtless as similar to those of its ally, as the two birds are in form and structure. 



The first specimen that came under my own observation, was received more than thirty years ago direct 

 from Popayan ; M. De Lattre killed it at Mocoa, " an ancient capital of the Indians, the environs of which 

 are inundated for five or six months of the year, which is situated on the borders of the Anthropophagous 

 nations, the Huitotos and Mesalles, and rarely visited by Europeans." Mr. Bridges found it in tolerable 

 abundance in Bolivia, whence he brought numerous examples to this country. I regret to say that this is 

 all that is at present known respecting it ; but from this meagre information I infer that the true habitat of 

 the species lies to the southward of the equator; its range probably extending over the whole of the eastern 

 dip of the Peruvian Andes, a portion of the country but rarely explored by naturalists. ^ 



In retaining my own name of smaragdicaudus for this species, I am not actuated by any desire to displace 

 that of Mocoa given to it by M. Bourcier, who has contributed so largely to our knowledge of this lovely 

 group of birds ; but have simply given it the preference because it so justly expresses the trivial name of 

 Green-tail commonly apphed to it : I may remark, moreover, that I believe it has slightly the priority in the 

 date of publication. 



The changes of plumage from youth to maturity, and the difference between the sexes, are precisely 

 similar to those of the Blue-tail. The young males, as might be expected, assume the green tint on the 

 tail at a very early period, but are far less brilliant than the adult ; in this state of plumage, specimens were 

 brought both by M. De Lattre and Mr. Bridges : in many of them a white mark occurred down the centre 

 of the back, similar to that observable in examples of the Blue-tail of the same age, but in every instance the 

 gorget of blue was absent. 



The male has the crown of the head rich shining yellowish metallic green ; on the throat a small gorget 

 of beautiful shining purplish blue; plumage of the body bronzy green, becoming of a browner hue on the 

 under surface ; wing-coverts and tips of the spurious wing-feathers shining green ; the remainder of the 

 wings purple-brown ; tail rich shining metallic green, with the exception of the basal half of the feather, 

 which is black ; a few white feathers stretch across the abdomen ; under tail-coverts green ; above and 

 behind the eye a very minute mark of white. 



The young male resembles the adult, but has the whole of the colouring, especially that of the crown, 

 far less brilliant; is entirely destitute of the gorget on the throat, and has the lateral tail-feathers much 



less developed. 



The female has the upper surface and wing-coverts golden bronze, a small mark of white behind the eye, 

 and a small streak of the same hue beneath it ; the under surface rufous, marked with bronzy green on the 

 flanks ; central tail-feathers shining green, changing to purple towards the tip ; lateral feathers black 

 glossed with deep blue, and tipped with white ; all the tail-feathers purplish black on their under surface ; 

 throat greyish white, with a round spot of dull green near the tip of each feather. 



The Plate represents two males and a female of the natural size on one of the common plants of Peru. 



