194 Proceedings of the Biological Society of Washington. 



Description. — Above Saccardo's olive, the pileum more brownish, the sides 

 of the head deeper brown, in more or less abrupt contrast ; wings dusky brown, 

 the middle and lesser coverts margined and tipped with olive buff, the inner 

 primaries and secondaries margined externally with cartridge buff, in 

 gradually increasing amount; inner webs of remiges margined with pale 

 buffy; upper tail-coverts Saccardo's umber; tail dusky brown, with indis- 

 tinct paler tip and edgings; throat and breast pallid neutral gray; rest of 

 under parts sulphur yellow (including under wing-coverts); "iris brown; 

 feet black; bill brown above, paler brown below." 



Measurements. 



Range. — From Guiana south to Buenos Aires, Argentina, and west to 

 the Andes. 



Remarks. — Immaturity is indicated in specimens with rusty cinnamon 

 edgings to the remiges and rectrices, and buffy under tail-coverts. Entirely 

 aside from this, however, and from the effects of wear, there is much varia- 

 tion, affecting the general coloration and the size and shape of the bill. In 

 some examples, notably the type-specimen of Myiarchus "fortirostris," 

 this member is shorter, stouter, and relatively higher, with the culmen more 

 rounded and the tip less strongly hooked than is usually the case in Myiar- 

 chus. Normally the upper parts in fresh plumage are as described, Sac- 

 cardo's olive, but occasionally they incline to grayish — in one specimen 

 (No. 284,412, U. S. National Museum, Victorica, Argentina) being almost 

 mouse gray. The yellow of the under parts is sometimes very pale or barely 

 indicated, and sometimes tinged with dull greenish. Wear and fading pro- 

 duce marked changes in color also. 



How many of the earlier Myiarchus records for South America east of 

 the Andes may pertain to the present form it is impossible to say, but it is 

 likely that a species with such a wide range must occasionally have fallen 

 under the eye of ornithologists. At any rate, Coues in 1872, with a speci- 

 men before him, failed to recognize it, and it was not until 1883 that von 

 Berlepsch pointed out its distinctive characters. His description appeared 

 in the Ibis for April of that year, while in the Journal fiir Ornithologie of 

 ostensibly even date Cabanis described a new species of the same group 

 under the name Myiarchus ferocior. We find, however, in the issue of the 

 latter journal a reference to the receipt of the April number of the Ibis, 

 which would give von Berlepsch's name a slight priority. By most authors, 

 however, ferocior has been either ignored or misapplied, and while Messrs. 

 Hartert and Venturi have apparently placed it correctly on the form to 

 which it belongs, they make the mistake of considering it a subspecies of 



