30 Proceedings of the Biological Society of Washington. 



Myiobius xanthopygus aureatiis Bangs, Proc. New England Zool. Club, 

 IV, 1908, 27 (Divala, Panama; orig. descr.; type now in coll. Mus. Comp, 

 Zool.; crit.). 



Myiobius xanthopygius aureatus Caeriker, Ann. Carnegie Mus., VI, 1910, 

 707 (Costa Rican localities and references; habits; nesting). 



Myiobius sulphureipygius aureatus Hellmayr, Proc. Zool. Soc. London, 

 1911, 1135, in text (Chiriqui; Pozo Azul, Costa Rica; crit.), 1136 (range). 

 —Chapman, BuD. Am. Mus. Nat. Hist., XXXVI, 1917, 466 (Alto 

 Bonito, Choco, Baudo, Novita, Juntas de Tamana, San Jose, and 

 Barbacoas, Colombia; Manavi, Ecuador; range; crit.). 



Myiobius sulphureipygius villosus (not of Sclater) Hellmayr, Proc. Zool. 

 Soc. London, 1911, 1135 (N6vita, Colombia; crit.). 



Subspecific characters. — Similar to Myiobius sulphureipygius sulphurei- 

 pygius, but color of breast and sides paler, and yellow of median under 

 parts slightly clearer in tone and more extended posteriorly, particularly 

 on the flanks and crissum. 



Measurements.— Male: wing, 62-66 (64); taU, 52-55 (53); bill, 10-12 

 (11); tarsus, 16.5-18.5 (17.8). Female: wing, 56-68 (62); taU, 49-56 

 (52); bill, 10-11.5 (10.8); tarsus, 14.5-18.5 (16.7). 



Range. — Honduras south through Colombia to Ecuador, west of the 

 Andes. 



Remarks. — No. 66,574, Collection Carnegie Museum, is a young bird 

 emerging from juvenal dress. The upper parts, wings, etc., are barred 

 with ochraceous buff feather-tips; the tertiaries have broad outer margins 

 of buf?y; the vertical spot and the yellow of the rump are wanting, and the 

 under parts are paler, duller, and more tinged with buffy, with the flanks 

 and crissum nearly white. 



M. sulphureipygius aureatus is not a strongly marked subspecies, but 

 may be recognized in series by the characters above specified. Examples 

 from Honduras and Nicaragua are clearly intermediate, but on the whole 

 seem best referred to the southern form. Birds from western Costa Rica 

 are pale by comparison, while those from Ecuador are bright; this is in 

 part due to season, however, and no further subdivision of the species is 

 advisable. The present race was formally distinguished by Mr. Bangs in 

 1908, after Mr. Ridgway had pointed out its characters. It occurs through- 

 out much of the territory occupied by M. atricaudus, but in somewhat 

 different haunts. In Costa Rica, according to Mr. Carriker, it is found 

 "up to an altitude of about 3,000 feet on the Caribbean slope and 2,000 

 feet on the Pacific. It is found only in the forest, usually near a little 

 brook, flitting about among the low limbs of the trees and shrubbery. 

 The birds are very silent; in fact I do not think I have ever heard them 

 utter more than a faint chirp." The same author describes the nest as 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. 



