76 TYRANNIDZ. 
p. 308°; Salv. P. Z. S. 1870, p. 199‘; Baird, Brew., & Ridgw. N. Am. B. ii. p. 363°; Ridgw. 
Ibis, 1886, p. 467°; Scl. Cat. Birds Brit. Mus. xiv. p. 2317. 
Empidonaz viridescens, Ridgw. Pr. U. S. Nat. Mus. vi. p. 413°. 
Quam precedentes pectore multo magis ochraceo. 
Hab. Costa Rica, Barranca }2, Dota Mountains, Grecia? (Carmiol), Quebrada Honda 
(v. Frantzius?), Irazu (H. Rogers); Panama, Volcan de Chiriqui*, Calovevora* (Arcé). | 
This species seems fairly separable from the more northern &#. salvini and E. bairdi, 
the most obvious character being the ochraceous tint on the chest. In some specimens 
the head and back are of a browner olive, but this is an evanescent character. Upon 
the specimens with the more olivaceous upper plumage Mr. Ridgway founded his 
E. viridescens, but with a typical specimen of E. flavescens before us, and others com- 
pared with the type of E. viridescens, we do not see how two Costa-Rican species can be 
established—some allowance must be made for age, season, &c. 
b. Rostrum angustulum. 
10. Empidonax hammondi. 
Tyrannula hammondi, Xantus de Vesey, Pr. Ac. Phil. 1858, p. 117’. 
Empidonax hammondi, Baird, B. N. Am. p. 199, t. 76. f. 17; Coues, Pr. Ac. Phil. 1866, p. 52°; 
Birds N. W. p. 257*; Key N. Am. B. ed. 2, p. 443°; Sumichrast, Mem. Bost. Soc. N. H. 
i. p. 557°; Baird, Brew., & Ridgw. N. Am. B. ii. p. 883"; Henshaw, U.S. Geogr. Surv. 
West 100th Mer. vy. p. 362°; Lawr. Bull. U.S. Nat. Mus. no. 4, p. 27°; Ridgw. Ibis, 1886, 
p. 467"; Man. N. Am. B. p. 844"; Scl. Cat. Birds Brit. Mus. xiv. p. 232”. 
E, obscuro similis et forsan haud distinguendus, caude rectrice utrinque extima pogoniis ambobus fere unico- 
loribus. Long. tota 5:2, ale 2°8, caude 2°3, tarsi 0°65, rostri a rictu 0°55. (Descr. exempl. ex Orizaba, 
Mexico. Mus. nostr.) 
Hab. Wustern Nortn America, from the Lesser Slave Lake southwards !.—Mexico, 
Sierra de Valparaiso in Zacatecas (Richardson), State of Vera Cruz (Sumichrast ), 
Orizaba (/. D. @), Gineta Mountains (Swmichrast®) ; Guatemata, Calderas 7500 feet, 
Pine-forest of Volcan de Fuego, between 10,000 and 12,000 feet (0. 8S. & F. D. G.). 
We are not at all sure that skins of this bird can always be distinguished from 
E. obscurus, the point chiefly relied upon lies in the colour of the outer web of the 
outermost tail-feather on either side, which in E. hammondi hardly differs from the 
inner web, but in £. obscurus is always whitish; moreover, E. hanunondi is usually a 
smaller bird than F. odscurus. We find, however, small birds with the outer web of 
the tail-feather paler than the inner, so that it becomes very difficult to determine 
accurately every individual. . hammondi has the long narrow bill of this section 
of Empidonaz, so that we have little doubt that it is with Z. obscurus that it should 
be compared, and this is the opinion of both Dr. Coues and Mr. Ridgway, though 
Mr. Henshaw considered that its affinity is with E. minimus 8. 
