224 FOEMICAEIIDiE. 



determined ; on the eastern side of the range the allied form, G. chiroleuca, takes its 

 place. 



The female of this species was described by Mr. Lawrence as Myrmeciza ferruginea^, 

 as was pointed out by Sclater and Salvin in 1864 in their paper on M'Leannan's 

 collections ^. 



2. Gymuocichla chiroleuca. 



Gymnocichla nudiceps, Moore, P. Z. S. 1859, p. 55 ' j Scl. & Salv. Ibis, 1859, p. 119^; Lawr. Ann. 



Lye. N. Y. ix. p. 109 \ 

 Gymnocichla chiroleuca, Scl. & Salv. P.Z. S. 1869, p. 417*; Salv. Ibis, 1869, p. 314'; Scl. Cat. 



Birds Brit. Mus. xv. p. 272 " ; Ridgw. Pr. U.S. Nat. Mus. xiv. p. 469 \ 



Prsecedenti similis, sed tectricibus alarum majoribus late albo marginatis, tectricibus minoribus externe oranino 



albis, plaga dorsali alba minore et nucha plumosa distinguenda. (l)escr. exempl. tj'p. ex Tucurriqui, 



Costa Eica. Mus. nostr.) 

 2 supra sctistaceo-bnmnea, .capite summo et cervice postica saturate ferrugineis ; alis fnscis extus obscure 



ferrugineis, tectricibus omnibus nigricantioribus et late rufo terminatis : subtus late ferrnginea. 

 S jvv. feminse sinulis, sed capite supra obscuriore, tectricibus alarum majoribus baud rufo terminatis. (Descr. 



feminae et maris juv. ex Santa Ana, Honduras. U.S. Nat. Mus.) 



Hah. Honduras, Omoa (Let/land ^ ^ ij^ Santa Ana (Wittkugel) ; Costa Eica, Tucurriqui 

 {Arce *). 



Though only two male specimens are known to us, this bird is evidently distinct 

 from G. nudiceps. Not only are the wing-coverts much whiter, but the denudation of 

 the head is not carried nearly so far back as in the allied species. This fact is of 

 importance, as G. chiroleuca thus serves as an intermediate step between G. nudiceps 

 and Myrmelastes immaculatus and the allied forms which we now place next the 

 genus Gymnocichla rather than in Thamnophilus, where they have latterly rested. 



Leyland obtained his specimen at Omoa, where he says only two or three birds came 

 under his notice. They frequent thickets, and make a noise like the breaking of small 

 twigs. 



Our single specimen was sent us from Tucurriqui, on the Atlantic side of the 

 Cordillera of Costa Rica, by our collector Arce, but without any note concerning it. 

 The authorities of the Derby Museum at Liverpool have kindly lent us Leyland's 

 specimen, so that its specific identity with the Costa Eica type is assured. 



We are indebted to Mr. Eidgway for an inspection of a female and a young male of 

 this bird. The former is darker on the upper surface than the female of G. nudiceps, 

 and has the edges of the wing-coverts more clearly defined. 



MYEMELASTES. 



Myrmelastes, Sclater, P. Z. S. 1858, p. 274. 



Thamnophilus, Scl. Cat. Birds Brit. Mus. xv. p. 180 (partim). 



The type of this genus is M. plumbeus, with which Thamnophilus immaculatus auct., 



