150 BROOKLYN INSTITUTE MUSEUM. SCIENCE BULLETIN 2. 6. 



Mr. Hellmayr, who has made a careful study of the South Ameri- 

 can members of the genus Polioptila, has, in his last word on the 

 subjects concluded that there are six recognizable races of P. livida. 



Only one of this number has been recorded from the Orinoco 

 region but as there are two others whose geographical distribution 

 when better known may be found to extend" to the territory under 

 consideration, I have included them in the following key. 



Key to Subspecies of Polioptila livida. 



a. Outer tail-feathers black at base of both inner and outer webs. . Polioptila livida plumbiceps. 



a'. Outer tail-feathers entirely white. 



b. Upper wing-coverts edged with whitish and broad white edgings of the 

 tertials reaching almost to the shaft. (Cayenne, Surinam, Lower Ama- 

 zonia from Para to Santarem) '. Polioptila livida livida. 



b' . Upper wing-coverts edged with pale bluish grey and white edges to 



tertials much narrower. (British Guiana, Rio Brancb in North Brazil) Polioptila livida innotata. 



Polioptila livida plumbiceps (Lawrence). 

 Polioptila plumbiceps Lawrence, Proc. Acad. N. Sc. Phila. XVIL 1865. 



p. ■^y (Venezuela). 

 Polioptila nigriccps Berlepsch & Hartert (non Baird) p. 9. 

 P[olioptila] livida plumbiceps Hellmayr, Noyit. Zool. XIV, 1907. p. 4. 



This species is common along the Middle Orinoco from Ciudad 

 Bolivar to the Falls of Atures, and less abundant above the falls 

 where specimens were collected at Maipures. 



A nest of this species, which the young were just leaving, was 

 found at Caicara June 20, 1907. It closely resembled nests of the 

 Blue-grey Gnatcatcher of Eastern North America, being a neat, trim, 

 lichen-covered cup, saddled on to a horizontal branch. The nest 

 measures outside : depth 45, diameter at middle of nest, 55 ; inside : depth 

 31; diameter at rim 35; diameter half way down 41 mm. It was about 

 5 m. from the ground on one of the branches of a Chaparo oak 

 that stood near the edge of the open savanna. It is by merest chance 

 that such a nest is discovered as it is so small, so inconspicuous and 

 its lichen covered walls match so exactly the color of the branch on 

 which it rests.2 



'Novitates Zoologicae XIV. 1907. pp. 4-5. 



-It seems somewhat doubtful to the writer if the nest described as that of Lawrence's Gnatcatchet 

 by Clark (Auk XIX. 1902. p. 266.) from Margarita Island could have belonged to that species. Gnat- 

 catcher nests certainly do not resemble those of the yellow Warbler. 



