DESCRIPTION OF THE ADULT MALE OF ACANTHIDOPS BAIRDI. 



BY ROBERT RIDGWAY. 



Tlu- specimen described below, probably the first adult male obtained 

 of this exeeediugly rare species (described in Vol. IV, p. 33(5, of these 

 Proceedings), was recently presented by the National Museum of Costa 

 Rica to that of the United States, through the courtesy of Mr. Anastasio 

 A 1 faro, director of the first named establishment, and Mr. Jose C. Zele- 

 don, discoverer of the original type specimen. 



The adult male of Acanthidops bairdi resembles very closely in col- 

 oration that of Haplospiza unicolor, of Brazil, but is darker and less 

 of a bluish cast, both above and below, and has the under mandible 

 chiefly light colored. Not having a specimen of the Mexican if. uni- 

 formis, I am unable to point out with exactness the differences from 

 that species; but judging from the description and remarks given by 

 Messrs. Salvin and Godman in Biologia Centrali- Americana, Arcs, pp. 

 366, 3(i7, it seems to come much closer to that species, if it be not actu- 

 ally the same! It would appear, however, to have decidedly a shorter 

 wing and longer tail, and longer tarsus than that bird. Whether or 

 not it is the same species or congeneric with H. uniformis, there can be 

 no doubt that it is generieafly distinct from H. unicolor, which has the 

 bill much shorter and more typically Friugilline, the tarsi shorter, aud 

 the nostrils more exposed. There can, I think, be no question that 

 Acanthidops comes very near to Haplospiza, and I am inclined to believe 

 that the so called II. uniformis belongs to Acanthidops and not to 

 Haplospiza, since Messrs. Salvin and Godman (loc. cit.) say that its 

 chief differences from II. unicolor consist in "a larger bill and longer 

 wings and stronger feet," as well as "rather darker" coloration. If this 

 view of its relationship proves correct, we would then have a Mid- 

 dle American genus, Acanthidops and a related Brazilian genus, Hap- 

 lospiza ; the first with two species, A. bairdi, of the Costa Eican high- 

 lauds, and A. uniformis, of southeastern Mexico. A case of somewhat 

 anomalous geographical distribution would thereby be satisfactorily 

 disposed of. 



Adult male (No. 114907, £ ad., El Alto, Poas, Costa Rica, July 27, 1888; A. Al- 

 faro).— Above uniform slate-black or blackish slate,* the concealed portion of the 

 wing-feathers decidedly black, this showing distinctly, in the closed wing, on the 

 remiges, which have only the edges dark slaty : under parts plain slaty, lighter than 

 upper parts,! slightly paler posteriorly, the Hanks tinged with light olive-brownish 

 and under tail coverts rather broadly bordered with the same. Upper mandible 

 brownish black, lower dull whitish, passing into dusky brownish on terminal third 

 and on basal portion of gonys; leys and feet horn-brown. Length (skin) 5.50, wing. 

 •-Mid, tail 'J.:!5, exposed cnlnieii .55, tarsus .85, middle toe .60. 



" Wry close to Fig. '2, Plate ii. of my "Nomenclature of Colors." 

 t Intermediate in tone between "slate-color" and "slate-gray" of my " Nomen- 

 clature of Colors." 

 196 



