TrEDUS. 25 



recognize it with certainty, no birds were obtained. Its note much resembles that of 

 Turdus merula. 



No true Blackbird is found in Costa Kica ; but in the Andes of South America, and 

 in the West-Indian island of Tobago, a second species, Turdus serranus, is commonly 

 met with. The close relationship of this species and T. infuscatus to the Old-World 

 T. merula is a curious fact of geographical distribution, and probably indicates the 

 remains of a much wider dissemination of the ancestral T. merula in past times, or that 

 a Blackbird inhabiting the high north has been pushed southwards in both America 

 and the Old World by advancing cold, and that, in America at least, these birds have 

 not followed the returning warmth, but have sought a congenial home in the mountains 

 of the south. 



D. Semimeeula. 

 Major : ptilods fere unicolor,fusca aut fusco-nigra. Sexus similes. 



17. Turdus nigrescens. (Tab. IV.) 



Tardus nigrescens, Cab. J. f. Orn. I860, p. 324'; Lawr. Ann. Lye. N. Y. ix. p. Q\^ ; v. Frantz. 

 J. f. Orn. 1869, p. 390'; Salv. P. Z. S. 1870, p. 180*. 



Brtmnescenti-nigrescens, alls et Cauda nigricantioribus ; subtus paulo dilutior ; rostro aurantiaco, pedibus 

 flavis. Long, tota 10-0, alse 5-5, caudae 4-5, rostri a rictu 2-2, tarsi 1-4. (Descr. exempl. ex S. Francisco, 

 Costa E,ica. Mus. nostr.) 



Juv. subtus gula et pectore cervinis nigro maculatis ; dorsi plumis medialiter cervino notatis. (Descr. av. juv. 

 ex Volcan de Oartago. Mus. nostr.) 



Hob. Costa Eica, Volcan de Cartago {Hoffmann, v. Frantzius, Arcs, J. Cooper), Dota 

 Mountains (Carmiol), San Francisco (Sogers) ; Panama, Volcan de Chiriqui (Arce). 



Twdus nigrescens was first described by Dr. Cabanis from specimens obtained by 

 Dr. Hoffmann in the Volcan de Cartago i, and. Dr. v. Frantzius tells us, it is found in 

 this volcano at an elevation of from 9000 to 10,000 feet above the sea ^. This mountain 

 seems to be the head quarters of the species in Costa Eica, as all collectors who have 

 worked there have obtained specimens. It is, however, also found in the Dota Moun- 

 tains, which lie at no great distance from Cartago. The only other locality in which it 

 has been obtained is the volcano of Chiriqui, whence several specimens have been sent 

 us by Arce ^. 



This Thrush seems to belong to a South-American section of the genus, found in the 

 Andes from Colombia to the neighbourhood of Mendoza, the best-known species of 

 which is Turdus gigas. It is, however, a well-marked species, and only remotely allied 

 to its next of kin. The sexes present scarcely any difference in plumage. 



BIOL, cbnte.-amer., Zool., Aves, Vol. 1, Sept. 1879. 4 



