176 GENEBA AND SPECIES. 



liarities of their economy, are yet to be ascer- 

 tained. 



Genus OBEOTROCHILTTS. The birds of this 

 genus are termed Hill stars; they are truly 

 Nivicolce, tenanting the range of the Cordilleras, 

 as high up as the margin of perpetual snow. 

 Below this margin is a belt of fertility, where 

 thousands of flowers, opening in succession, 

 afford them an abundant supply both of insects 

 and nectar. Most probably they descend to lower 

 altitudes during the inclement season, and regu- 

 late their degree of ascent according to the 

 unfolding of the blossoms, to which they are 

 more especially attracted. In this genus the 

 bill is longer than the head, slender, and slightly 

 arched ; the wings are moderately large and 

 powerful ; the tail is large, and graduated or 

 rounded, consisting of narrow, rather pointed 

 and rigid feathers ; the feet are strong and the 

 tarsi plumed ; the gorget is ample and most 

 splendid ; and the abdomen presents a chestnut 

 brown or black longitudinal fascia, acute at its 

 anterior origin, and more or less extensive. 



The females are plain, with the throat spotted. 



The nest is usually attached by cobwebs to 

 the sides of rocks, or to blocks of stone. 



Six species are at present recorded, viz. : 

 Tr. Estella, D'Orbigny, from Bolivia ; O. leuco- 

 pleurus, Gould, from the Chilian Cordilleras; 

 T. Chimborazo, Bourc. from Lima ; T. Pichincha, 

 from Quito ; O. Adela, D'Orbigny, from Bolivia; 



