636 Annals of the Carnegie Museum. 



the separation of the northern bird. The species has a very general 

 distribution over Costa Rica, covering the lowlands of both coasts 

 (but is very rare in Guanacaste) up to 3,000 feet on the Caribbean (Juan 

 Vinas, one specimen by Boucard) and up to perhaps not more than 

 1,500 to 2,000 feet on the Pacific. They frequent high grass along 

 streams, old abandoned fields, bushes, and weeds in pastures and the 

 edges of woodland, always keeping near the ground, and, when flushed, 

 will make only low short flights like a rail. They are very noisy, 

 making a curious rattling, chattering noise when disturbed. Breeding 

 begins in May and continues until the end of July, the birds probably 

 rearing two broods. I observed many nests in the vicinity of Guapiles, 

 Jimenez and El Hogar as well as at Pozo Azul de Pirris and in the 

 Terraba Valley, and all were built almost exactly alike and precisely 

 after the manner of .S". albescens as given by Salmon (Biologia, II, 

 148). 



The nest is placed in a small shrub or tree, is built entirely of twigs, 

 even sticks as large as a lead-pencil being used. The shape is either 

 globular or elliptical, with a long tunneled entrance made of inter- 

 laced twigs just large enough for the passage of the bird. The nest 

 itself is usually about ten to twelve inches in diameter and the enter- 

 ing passage-way from eight to fourteen inches in length. The top of 

 the structure is covered over with a mat of leaves and trash in some 

 instances, but not always. There is usually no lining whatever to the 

 nest cavity, the eggs being placed on the twigs composing the bottom 

 of the nest. From two to three eggs are laid, which are pale bluish - 

 white without markings. Measurements : 21 to 22X16 to 17 mm. 



370. Acrorchilus erythrops rufigenis (Lawrence). 



Synallaxis erythrops (not of Sclater) Lawrence, Ann. Lye. N. Y., IX, 1868, 105 

 (Barranca and Dota [F. Carmiol], Birris [Zeledon]). — Frantzius, Jour, fur 

 Orn., 1869, 304 (Costa Rica.) — Boucard, P. Z. S., 1878, 59 (Volcan de 

 Irazu and Navarro). — Zeledon, An. Mus. Nac. de C. R., I, 1887, 113 (Rio 

 Sucio). 



Siptornis erythrops Sclater, Cat. Birds Brit. Mus., XV, 1890, 60, part (Costa 

 Rica to Ecuador). — Salvin and Godman, Biol. Centr.-Am., Aves, II, 1891 

 151, part (Irazu [Rogers]; Costa Rican references). 



Synallaxis rufigenis Lawrence, Ann. Lye. N. Y., IX, 1868, 105 (Costa Rica, 

 Garcia collection). — Frantzius, Jour, fur Orn., 1869, 304 (Costa Rica). — 

 Salvin, P. Z. S., 1870, 191 (Costa Rica [Carmiol]). — Zeledon, An. Mus. 

 Nac. de C. R., I, 1887, 113 (Costa Rica). 



Siptornis rufigenis Sclater, Cat. Birds Brit. Mus., XV, 1890, 60 {$ — Costa 



