330 



NOKTII AMERICAN BIRDS. 



1*4^9 



cult genus, we are indebted to a recent monograj)!! "by Pr. Coues, in the 



Proceedings of the 

 rhiladeli)hia Acad- 

 emy, for June and 

 July, 1872 (pp. 56- 

 81). With the same 

 material for our in- 

 vestigations, we have 

 been led, after a very 

 careful perusal of the 

 valuable paper men- 

 tioned, and tedious 

 critical comparison 

 cf the large material 

 at our command, to 

 adopt a somewhat 



Myiarchus mexicanus. difficult vlcW of the 



relationship of the forms characterized. The following synopsis expresses 

 their affinity as at present understood : — 



Common Characters. Above olivacec-s. usually uniform, sometimes darker, 

 sometimes more ashy, on the head above. Head and jugulum more or less ashy, 

 though the latter is sometimes very pale. Rest of lower partvS sulphur-yellow, 

 sometimes almost or quit<? white. Primaries, secondjvries, and rectrices usually 

 more or less edged on either web with rufous; but sometimes entirely destitute 

 of this color. - 



Species and Varieties. 



A. Bill sub-conical ; sometimes nearly terete, its depth enun^ 

 its breadth in the middle portion; its lateral outlines ut> 

 basally ; terminal hook abrupt, strong. (Myionar.) 



1. M. tyrannulus. No trace of rufous edgings on either wings or tail. 

 Above ashy-olive, the pileum similar, the outer webs of wing-coverts and 

 secondaries edged with whitish. Head, laterally and beneath, ashy, the 

 throat and jugulum more whitish rest of lower parts sulphur-yellow. 

 Tail slightly rounded. 



Pileum and nape umber-brown ; upper surface umber-grayish. Bill 

 dark brown. Wing, 3.;")0-3.70; tail, 3.60-3,90; culmen, .90 -,95; 

 tarsus, .80 - .90. Hab. South and Central America, from Bolivia Jind 

 Southern Brazil to Costa Rica . . . * . var. tyraiiiinlus} 



Whole head and neck pure a^h, paler on the throat, and darker on the 

 pileum; upper surface greenish-ash. Bill black. Wing, 3.70 ; tail, 4.00; 

 culmen, .82 ; tarsus, .91. Hab. Ecuador and Guayaquil. 



, _ ^ ^ var. phaeocei^h alus? 



1 Mifiarch US fj/ranv iiluJi CMiJLL.), Cofes. 3fiiscy:a2xi tyranmilm, Mitll, (G. R. Or, Hand List, 

 No. 5,527). Mijiarchus t. CouEs, P. A. N, S, Phila. July, 1872, 71. {M. aurora, Rodd. ; Jlavi- 

 ventris, SpErn. ; fcrox, Gm. ; sv:ainsoni, Caban. ; panamcnsis, Lawr. ; vcncztielensis, IjAWR.) 



2 Myiarchus ty ran nnhis, var. phceoccphrilus {^cla.tis.v). Myiarchus phccocephtr I us, Scl, P. Z, S. 

 1860, 481.— Coues, P. A, X, S. 1872, 73. 



> or exceeding, 

 iiely divergent 



