502 BULLETIN nO, UNITED STATES NATIONAL MUSEUM. 



Costa Rica (Tabacales; Dota; La Palma de San Jose; Cervantes; 

 Barranca; Tucurriqui; Naranjo; La Candelaria; La Lagiina; San 

 Mateo; Volcan de Irazu; Volcan de Barba; Cariblanco de Sarapique; 

 Coliblanco; San Carlos; Carrillo; El Achiste; Buena Vista), and 

 northern Panama (Calovevora; Calobre; Chitra; Volcan de Chiriqui; 

 Boqnete). 



Miti'ephorus auraniiwentris Lawrence, Ann. Lye. Nat. Hist. N. Y., viii, LSfiT, 178 

 (Tabacales, Costa Rica; colL U. S. Nat. Miis.); ix, 1868, 114 (Tabacales, La 

 Palma, and Dota, Costa Rica). — Salvin, Proc. Zool. Soc. Lond., 1870, 198 

 (Calovevora, Panama). — Frantzius, .ToTirn. fiir Orn., 1869, 308 (Candelaria, 

 Costa Rica). — Boucard, Proc. Zool. Soc. Lond., 1878, 64 (La Laguna, Naranjo, 

 Candelaria, and San Mateo, Costa Rica, 4,000 to 8,000 ft.; habits). 



[Mitrephorus] aurantiiventris Salvin, Il)is, 1869,315, in text (crit.). — Sclater and 

 Salvin, Nom. Av. Neotr., 1873, 51. 



[Pyrocephahis] aiirantiiveMris Gray, Hand-list, i, 1869, 361, no. 5489. 



Mitrephanes aurantiiventris Coues, Bnll. Nutt. Orn. Club, v, Jan., 1882, 55. — 

 Sclater, Cat. Birds Brit. Mus., xiv, 1888, 219 (Tucurriqui, IrazAi, and Bar- 

 ranca, Costa Rica; Calobre, Chitra, Volcan de Chiriciui, and Calovevora, 

 Panama). — Salvin and Godman, Biol. Centr.-Ain., Aves, ii, 1859, 67. — 

 Bangs, Proc. New Engl. Zool. Clul), iii, 1902, 37 (Boquete, Panama, 4,000 

 to 4,800 ft.). 



M[itrephanes] aurantiiventrii Berlepsch and Stolzmann, Ibis, 1894, 391, in text. 



[Mitrephanes] aurantiiventris Sharpe, Hand-list, iii, 1901, 136. 



Mitrephorus phseocercus (not of Sclater) Lawrence, Ann. Lye. N. Y., ix, 1868, 114 

 (Costa Rica;=young). — Frantzius, Journ. fiir Orn., 1869, 308 (Costa Rica). 



Genus DELTARHYNCHUS Ridgway. 



Deltarhijnchusa Ridgway, Proc. U. S. Nat. Mus., xvi, no. 955, Oct. 25, 1893, 606. 

 (Type, Myiarchus flammiilalKs Lawrence.) 



Rather small Tyrannidas (wing about 75 mm.) related to Myiarclms 

 but differing in relatively shorter and broadly triangular bill, wholly 

 exposed, circular, and less widely se])arated nostrils, shorter tentli 

 primary (equal to first instead of equal to or longer than third), and 

 ]>artly streaked under parts. 



Bill about half as long as head, much depressed, broadly triangidar 

 in vertical profile, its width at frontal antise nearly equal to distance 

 from nostril to tip of maxilla, nearly if not quite equal to length of 

 gonys, and twice its depth at same point ; exposed culmen longer than 

 middle toe without claw, distinctly ridged, straight to near tip, where 

 rather abruptly decurved, the tip of maxilla obtusely uncinate; gonys 

 much longer than mandibular rami, slightly convex; maxillary 

 tomium nearly straight, minutely notched subterminally. Nostril 

 wholly exposed, nearly circular, much nearer to culmen than to com- 

 missure, opening almost vertically. Rictal bristles well developed, and 

 feathers of chin, malar antiae and frontal antise with distinct bristly 

 points,' the first recurved, the last arched and semierect. Wing 



" Je'Ara, delta; /jVyx^'S, bill, from ils l)roadly triangular bill. 



