Todd — Studies in the Tyrannida. 27 



Specimens examined. — Colombia: La Murelia, Caqueta, 1. Venezuela: 

 Rio Yuruan, 3; Suapure, 2. British Guiana: Mount Roraima, 3; Cama- 

 cusa, 1; unspecified, 1. French Guiana: Tamanoir, 16; Pied Saut, 4. 

 Brazil: Obidos, 4; Coloniado Veado, Obidos, 1; St. Antonio do Cachoeira, 

 1; Manacapuru, 1; Avojutuba, Rio Negro, 1. Total, 39. 



Myiobius semiflavus Todd. 



Myiobius semiflavus Todd, Proc. Biol. Soc. Washington, XXXII, 1919, 

 114 (El Tambor, Santander, Colombia; orig. descr.; type in coll. Carnegie 



Mus.). 



Description. — Male: above plain olive green, the pileum with a partially- 

 concealed vertical spot of empire yellow, the rump pale lemon yellow; 

 wings dusky, the remiges margined externally with buffy citrine, most 

 conspicuous basally and on the secondaries; upper tail-coverts and tail dull 

 black; beneath (including under wing-coverts) pale lemon yellow, the throat 

 and crissimi still paler (Martius yellow), the breast and sides shaded with 

 pyrite yellow or yellowish citrine ; tibiae usually more or less shaded with 

 citrine; inner margins of remiges buffy below; "iris brown; feet pale 

 leaden blue; bill black, flesh-color below." Female similar, but the verti- 

 cal spot wanting or merely indicated. 



Measurements. — Male (four specimens): wing, 65-68 (66); tail, 53-59 

 (56.5); bill 11-12 (11.5); tarsus, 17-18.5 (17.5). Female (three speci- 

 mens): wing, 62-64 (63); tail, 51-56 (54); bill, 10.5-11 (10.7); tarsus, 

 15-17 (16). 



Range. — Known only from the type-locality, in the valley of the Rio 

 Lebrija, northeastern Colombia. 



Remarks. — This species is easily distinguished by its generally rich 

 coloration and decidedly yellow under parts, which are much brighter 

 than in any other form of this group. Although perfectly distinct, it 

 seems to be most closely related to M. barbatus, and may have been devel- 

 oped therefrom by isolation. Certainly it has nothing to do with M. 

 atricaudus, one of whose forms it approximates geographically. It is known 

 at present only from the seven specimens listed below, but will probably 

 be found to have a more extensive range, covering perhaps the whole of the 

 valley of the middle Magdalena. 



Specimens examined. — Colombia: El Tambor, 7. 



Myiobius sulphureipygius sulphureipygius (Sclater). 



Tyrannula sulphureipygia Sclater, Proc. Zool. Soc. London, "1856," 

 1857, 296 (Cordova, Vera Cruz, Mexico; orig. descr.; type now in coll. 

 Brit. Mus.). 



Myiobius citrinopygus Cabanis and Heine, Mus. Heineanum, II, 1859, 

 67, note (Mexico; new name for Tyrannula sulphureipygia Sclater, on 

 grounds of purism). — Heine and Reichenow, Nom. Mus. Heineani 

 Orn., 1883, 144 (Mexico; syn.). 



Myiobius sulphureipygius Sclater, Proc. Zool. Soc. London, 1859, 45 

 (range), 384 (Playa Vicente, Oaxaca, Mexico). — Sclater, Ibis, 1859, 



