306 BIRDS OK THE REPUBLIC OF PANAMA PART 2 



Panama the bill is black, a character that continues in the birds of 

 western Colombia and much of Ecuador and Peru. Males of the 

 different groups, with one exception, have an ornamental crown 

 cap that differs in brighter glittering color from the metallic iridescence 

 of the rest of the upper surface. The exception is the bird of Panama, 

 named assimilis by Lawrence. In this, crown and upper surface are 

 metallic green, except that in a few some of the tiny feathers of 

 lores and anterior forehead glow. The difference is so definite that 

 it seems reasonable to list assimilis as a separate species that, in 

 addition, is marked by upper tail coverts which are shorter in relation 

 to the length of the tail. The several other black-billed groups found 

 across northern South America all have the distinct crown cap and 

 relatively longer upper tail coverts. In Costa Rica Chlorostilbon 

 assimilis ranges in the lowlands of the southwest, where it has been 

 collected at Boruca and Buenos Aires, with 1 record, based on a 

 specimen from Underwood, from the Dota region. 



Simon (loc. cit., p. 290) includes "Rep. de Panama" in the range 

 of his subspecies "pumila (Gould)" in error, as that form is not 

 found in the Republic. 



THALURANIA FURCATA (Gmelin) : Fork-tailed Woodnymph, 

 Colibri de Coronilla 



Trochilus jurcatus Gmelin, Syst. Nat., vol. 1, pt. 1, 1788, p. 486. (Cayenne.) 



Medium in size ; male with green throat, crown deep blue in western 

 Panama, or shining green in Darien ; female gray underneath with 

 blue, white-tipped tail, and black bill. 



Description. — Length, male 112-115, female 90-92 mm. Adult male 

 with fairly long, forked tail; forehead and front of crown brilliant 

 violet-blue in birds from central and western Panama, bright shining 

 green in those of Darien ; back of head, hindneck and upper back 

 black, with a sheen of dull green ; center of back, lesser and middle 

 wing coverts deep violet-blue ; lower back and rump dark bluish 

 green, primary coverts and tail very dark blue; wings dusky with a 

 violet sheen ; foreneck and upper breast brilliant emerald-green ; lower 

 breast and abdomen dark violet-blue; femoral area white; under 

 tail coverts steel-blue, mixed more or less with white. 



Female, above metallic green ; forecrown duller, with the feathers 

 dull green tipped with bronze ; wing coverts bluish green ; middle pair 

 of rectrices greenish blue at base, then dark blue, some becoming 

 black at tip ; the two outermost tail feathers tipped with white or gray- 

 ish white ; wings dusky ; lower surface grayish white, with the sides 



