Todd — Studies in the Tyrannidce. 191 



Pipromorpha semischistacea Ridgway, Bull. U. S. Nat. Mus., No. 50, IV, 



1907, 454 (diag.), 458 (descr.; range; references). — Carriker, Ann. 



Carnegie Mus., VI, 1910, 712 (Costa Rica; references; crit.). 

 Pipromorpha assimilis dyscola (not Mionedes assimilis dyscolus Bangs) 



Rendahl, Arkiv for Zoologi, XII, No. 8, 1919, 24 (San Juan del Norte, 



Nicaragua; crit.). 



Description. — Adult: above, including sides of head, and wings and tail 

 externally, plain olive green, the pileum slightly darker and duller; median 

 and greater wing-coverts with indistinct paler (citrine) tips, and inner 

 secondaries with more or less obvious buffy edgings and tips; inner margins 

 of all the remiges pale buffy toward the base; chin and throat dull grayish, 

 tinged with olive, and passing into pale citrine or olive lake on the breast, 

 where it is more or less flammulated with chamois color or honey yellow, 

 which color covers the rest of the under surface, including the under wing- 

 coverts; sides and flanks usually with some darker shading; ''iris dark 

 hazel; bill dark brown, paler at base below; feet plumbeous." 



Young in juvenal dress (Mus. Comp. Zool. 74,629) similar, the posterior 

 under parts more decidedly buffy. 



Measurements.— Male: wing, 64-69 (67.5); tail, 50-55 (53); bill, 11.5-13 

 (12); tarsus, 15-16.5 (16). Female: wing, 61-66 (63); tail, 46-52 (49); 

 bill, 11-13 (11.5); tarsus, 14.5-16 (15.3). 



Range. — Tropical Zone of southern Mexico (States of Vera Cruz and 

 Tabasco), southward through Central America to eastern Costa Rica. 



Remarks. — Sclater at first referred specimens from Cordova, Vera Cruz, 

 Mexico, to Mionedes oleagineus, but shortly thereafter he was led to 

 describe them as a new species, which he called assimilis. In 1888 Sclater 

 reduced this to a subspecies of oleagineus, while Salvin and Godman declined 

 to recognize it at all. The fine series we have examined in this connection, 

 however, indicates that while the two forms are closely related, they are in 

 our judgment best kept specifically separate, as claimed by Mr. Bangs and 

 indorsed by Mr. Ridgway. 



Ordinarily the species is subject to comparatively little variation, judg- 

 ing from the series examined. Some specimens have the throat grayer, in 

 others it is more olivaceous and paler, but this is doubtless due to the fresher 

 condition of the latter. The outer primaries are decidedly narrowed in 

 fourteen out of thirty-seven specimens, while others still show traces of such 

 a condition. Both sexes show this feature, assuming the specimens are 

 correctly determined, and it may be purely dependent on age. 



The type-specimen of Mionectes semischistaceus Cherrie, from Guayabal, 

 Costa Rica, is an individual which has every appearance of being an 

 abnormally colored example of the present form. It agrees in every respect 

 with skins of assimilis from eastern Costa Rica, except for having the upper 

 surface, from the forehead down to the middle of the back, deep neutral 

 gray, and the sides of the neck and throat shaded with the same color. The 

 specimen remains unique, and coming as it does from a region where birds 

 of the usual type are known to occur, it is extremely unlikely that it is any- 

 thing more than a freak. A careful examination shov/s that on one wing 



