50 Nelson North American Mainland Myiarchus. 



or without a fine grayish edging; secondaries narrowly edged with light 

 drab often tinged with greenish; tertials dingy whitish sometimes in 

 clining to drab; wing coverts drab; inner borders of wing feathers sal 

 mon buffy; chin, throat and breast ash gray; abdomen and under tail 

 coverts canary yellow varying to sulphur yellow. 



Description of young in first plumage. Crown dull sooty black; back 

 dingy olive: upper tail coverts sepia brown edged with dark russet; wing 

 coverts, tertials and secondaries rusty cinnamon, palest on tertials; inner 

 primaries thinly edged with russet; inside of wing feathers bordered 

 with salmon buffy; tail feathers narrowly bordered on both webs by 

 cinnamon rufous; chin, throat and breast ashy gray; abdomen and un- 

 , der tail coverts primrose yellow. 



Measurements. Averages of ten adult males from northern Colombia: 

 Wing, 81.7 (80-83); tail, 76.3 (74-78); culmen, 17.1 (17-18); tarsus, 19.6 

 (18.5-20.5). 



Averages of five adult females from northern Colombia: Wing, 77.2 

 (73-83); tail, 72 (68-76); culmen, 16.6(16-17); tarsus, 19.4(18-20.5). 



General notes. The adults of this species in size and general style of 

 coloration resemble M. nigricapillus and M. bangsi, except that they 

 completely lack the rufous edgings to wings and tail found in those 

 birds. The first plumage of nigriceps is much like the young of law- 

 rencei but the upper parts are darker and the rufous borders to the tail 

 feathers are decidedly narrower. Whether the ranges of this species 

 and M. bangsi overlap or are complementary remains to be determined. 



Myiarchus brunneiceps Lawrence, Ann. Lye. Nat. Hist. N. Y., VII, 

 327, June, 1861, from Lion Hill, Panama, is a synonym of M. nigriceps. 



M. nigriceps is a wide ranging South American species with M. law- 

 rencei and subspecies as its nearest relatives in North America. 



