246 PTEROPTOCHIDZ. 
Fam, PTEROPTOCHIDA. 
This is another peculiarly Neotropical family of Tracheophone, containing eight 
genera, several of the most characteristic of which are restricted to Chili and the 
southern part of South America. Scytalopus, however, ranges throughout the Andes, 
and a species of this genus has lately been discovered in Costa Rica. 
SCYTALOPUS. _ 
Scytalopus, Gould, P. Z.S. 1836, p. 89; Scl. Cat. Birds Brit. Mus. xv. p. 337. 
Mr. Sclater recognizes nine species of this genus, but several others have been 
described which were unknown to him. The species described below is also an addi- 
tion to the list. 
The range of Scytalopus is very extended, and reaches from the Straits of Magellan 
to Colombia and Venezuela and also to Costa Rica. It is unrepresented in Guiana, 
but occurs in South-eastern Brazil. 
All the species are small Wren-like birds. The wings are short and much rounded 5 
the tail moderate, consisting of soft feathers the stems of which are slender ; the bill is 
short and somewhat compressed towards the tip, the maxilla having a distinct notch 
near the end of the tomia. The nasal covers are very tumid, and the nostrils are 
elongated slits lying along the lower edge of the nasal fossa. 
1. Scytalopus argentifrons. 
Scytalopus argentifrons, Ridgw. Pr. U. 8. Nat. Mus. xiv. p. 4757. 
Supra saturate schistaceo-brunneus, fronte et pileo antico argenteo-cinereis, dorso postico et tectricibus supra- 
caudalibus saturate brunneis his rufescentioribus: subtus obscure schistaceus, ventre medio albicanti- 
cinereo, hypochondriis et tectricibus ad apices ferrugineo-rufis; alis et cauda dorso fere concoloribus: 
rostro nigro ad rictus carneo, pedibus corylinis. Long. tota 4:30, ale 2°15, caude 1°55, rostri a rictu 0°55, 
tarsi 0°8, dig. med. 0°68. (Descr. maris exempl. typ. ex Volcan de Irazu, Costa Rica. U.S. Nat. Mus.) 
Juv. supra undique nigricanti-fusco et saturate brunneo indistincte transfasciatus: subtus saturate fuscus, 
mento et gutture cinerascentibus cervino mixtis, abdomine ferrugineo notato. (Descr. juy. ex Volcan de 
Irazu, Costa Rica. U.S. Nat. Mus.) 
Hab. Costa Rica, Volcan de Irazu (A. Alfaro 1). 
We are indebted to the authorities of the United States National Museum for the 
loan of two specimens (the types described by Mr. Ridgway) of this interesting species, 
which was discovered by Don Anastasio Alfaro on the Volcan de Irazu in April 1891, 
and forms an interesting and important addition to the fauna of Costa Rica. 
S. argentifrons has its nearest ally in the southern S. analis,a bird described by 
