8YCALI8.— ACANTHIDOPS. 433 



hardly in a position to speak definitely as to its status with reference to S. luteola. A 

 Mexican skin sent to Mr. Sclater by the Parisian dealer Parzudaki formed the basis of 

 the original description ^; Sumichrast subsequently found it near Orizaba^. It has only 

 once been noticed in Guatemala, Salvin having shot a young bird at the edge of some 

 high grass on the plain of Dueiias in September 1862. There was another specimen 

 with it, and the two were feeding on grass-seeds ^. 



Oenus Fringillidarum incertce sedis. 



ACANTHIDOPS. 



Acanthidops, Ridgway, Pr. U. S. Nat. Mus. iv. p. 335 (1882); Scl. Ibis, 1884, p. 241. 



In 1882 Mr. Eidgway described a bird from Costa Rica under the name oi Acan- 

 thidops bairdi from a specimen sent him by Mr. Zeledon. He considered it to belong 

 to the Dendrocolaptidse, and to be most nearly related to Automolus, Phacellodromus, 

 &c. He sent us the type for inspection, and also a second specimen from the same 

 country ; these we carefully examined with Mr. Sclater, who wrote a note on the 

 subject in 'The Ibis' for 1884. It was proved that Acanfhidoj)s has nine and not ten 

 primaries, and therefore, according to the prevailing system of classification, it must go 

 with the Oscines and not the Tracheophones. Our own impression was that both 

 specimens (marked male and female) were young birds in their first full plumage, and 

 to this cause was to be attributed the sharpness of the ends of the rectrices. If this 

 be so, we may look for a very difiisrently coloured bird in the adult male. At the same 

 time, if the suggested relationship to Chrysomitris is a real one, the coloration of the 

 adult may be as in C. pinus, and in that case not very different from that of the young. 

 Then, again, the exposed nostrils militates against any alliance with Chrysomitris, the 

 position suggested for it by Mr. Sclater. 



For the present we suspend our judgment as to the position of Acanthidops, pending 

 the receipt of more specimens. 



In the meantime we give the substance of Mr. Eidgway's description of the genus 

 and species : — 



Bill about as long as the middle toe, cuneate in all its profiles, somewhat swollen 

 basally, the culmen and lateral outlines decidedly concave in the middle portion; 

 mandibular tomia very strongly inflexed, with a prominent angle near the base, anterior 

 to which the edge is decidedly concave ; maxillary tomia with a decided notch near the 

 base, immediately above the mandibular angle; gonys very long (about equal to the 

 exposed portion of the culmen) ; nostril exposed, small, longitudinal, occupying less 

 than the lower half of the nasal fossa. Tarsus a little longer than the middle toe and 

 claw, divided into about six plates, but these entirely fused on the outer side, except 

 the lower one, which is distinct ; lateral toes equal, the points of their claws falling 



BIOL. CBNTR.-AMER., Aves, Vol. I., November 1886. 55 



