708 Annals of the Carnegie Museum. 



I found them breeding commonly about Guapiles, Jimenez, and El 

 Hogar, and the nests were invariably of similar construction and placed 

 in the same situation, viz., suspended from a slender vine or the tip of a 

 pendant branch hanging over a pool in a creek making its way through 

 the thick forest. I also took two badly incubated eggs at Guaitil, 

 May 4, from a nest of similar construction and situation. The birds 

 began breeding in the Santa Clara Valley about April 24 to May 10, at 

 which time a nest could always be found by following a little brook through 

 the forest for a short distance. The nest is a purse-shaped mass of grass, 

 roots, and bark-fibres, about eighteen inches long, very slender at the upper 

 end and about three and one-half inches in diameter at the largest 

 part (about four inches from the bottom). The entrance to the cavity 

 of the nest is on one side, four inches from the bottom and protected by 

 an overhanging flap of the material of the nest. The eggs are invariably 

 two in number, creamy white, sometimes with a roseate tinge, and thickly 

 speckled, streaked, and scrawled over the entire surface with bright chest- 

 nut-rufous, heavier at the larger end, in the form of a wreath or cap. 

 Sometimes the markings have a decided purplish color. Measurements: 

 17 to 20 X 12 to 14 mm.; average, 18.5 X 13 mm. 



471. Myiobius barbatus atricaudus (Lawrence). 



Myiobius barbatus Sclater, P. Z. S., 1869, 282 (Babahoyo, Ecuador); Cat. 

 Birds Brit. Mus., XIV, 1888, 199, part (Veragua to Ecuador). — Salvin 

 and Godman, Biol. Centr.-Am., Aves, II, 1889, 56 (one Costa Rican ref- 

 erence). 



Myiobius atricaudus Lawrence, Ibis, 1863, 183 (Lion Hill, Panama [M'Leannan]) 

 — Nutting, Proc. U. S. Nat. Mus., V, 1882, 396 (La Palma de Nicoya). 



Myiobius barbatus atricaudus Ridgway, Birds N. and Mid. Amer., IV, 1907, 488 

 (Peru to western Costa Rica: La Palma de Nicoya, Pozo Azul de Pirris, 

 Rio Naranjo). — Bangs, Auk, XXIV, 1907, 302 (Boruca and El Pozo de 

 Terraba [Underwood]). 



Bangs Collection: Buenos Aires and El General de Terraba; Pozo Azul 



de Pirris (Underwood). 

 Carnegie Museum: Boruca and Buenos Aires (Carriker) ; Pozo Azul de 



Pirris (Underwood). Four skins. 



This Myiobius is restricted in Costa Rica to the southwestern Pacific 

 coast region, from the Gulf of Nicoya southward, and from sea-level up to 

 about 1,500 feet. It isveryrare north of theTerraba Valley and even there 

 is much less abundant than M. xanthopygius aureatus. In life this species 

 can be distinguished from the last named species at a glance, for its actions 

 are very different. It is always seen rather high up in the trees, flitting 



