32 Nelson North American Mainland Myiarchus. 



Mexico by Mr. Wollweber but no definite locality mentioned. 



Breeding range. From the Rio Grande Valley in southern Texas, south 

 along the tropical and subtropical parts of eastern Mexico to Yucatan, 

 Cozumel Island, Belize, northeastern Guatemala, and Honduras (Ceiba). 

 Migratory only in northern part of its range. 



Zonal distribution Lower Sonoran, Arid and Humid Tropical. 



Specific characters. Crown olive; back brownish olive; wings and tail 

 (on both webs) strongly margined with rufous. 



Description offrexh plumage. Top of head olive with a greenish shade, 

 feathers indistinctly streaked with darker centers; back dull brownish 

 olive, slightly grayer than crown; back of neck slightly grayer than back, 

 forming an indistinct collar; upper tail coverts dingy raw-umber brown, 

 sometimes edged with dull rusty; wing coverts broadly edged with dull 

 brownish white: tertials edged with white, tinged with pale greenish; pri 

 maries, except first, edged along middle with dark rufous; chin, throat 

 and breast ashy gray, palest on chin; abdomen and under tail coverts 

 deep primrose yellow sometimes slightly washed with gray (especially in 

 Yucatan and Cozumel specimens); outer web of outer tail feather vary 

 ing from plain drab to lighter more grayish brown; inner web of outer 

 feather with a band of dusky along shaft from near base to tip, usually 

 a little broader in middle where it occupies from one-fifth to over one- 

 half the width of web; other tail feathers, except middle pair, 

 similar, but dusky band decreasing toward middle of tail. 



Measurements. Averages of seventeen adult males from northeastern 

 Mexico: Wing, 102.4 (98-106); tail, 95.4 (90-98); culmen, 21.3 (20-23); tar 

 sus, 23.5 (22.5-25;. 



Averages of five adult females from northeastern Mexico: Wing, 95.7 

 (94-98); tail, 90 (88-91); culmen, 19.9 (19-21.5); tarsus, 22.4 (21-23). 



General Notes. In worn or faded plumage much of the greenish wash 

 on upperparts is lost and the coloration closely resembles that of 

 magister. Specimens from the State of Vera Cruz average larger than 

 those from the Rio Grande while those from Yucatan and Cozumel 

 Island are smaller than from any other part of their range. Cozumel 

 birds are also slightly darker than those from elsewhere. This form 

 reaches the borders of the tableland along river valleys but does not in 

 habit the tableland proper. Its range comes in contact with that of 

 magister only through the low gap in the elevated continental area at the 

 Isthmus of Tehuantepec. A large proportion of specimens have the 

 dusky line along shaft on inner web of outer tail feather appreciably 

 broadest in the middle and narrowing toward each end, but in some in 

 dividuals it is nearly the same width most of its length and in a few 

 cases becomes a little broader near the tip. 



A typical specimen in the Bangs Collection taken by Mr. W. W. 

 Brown, January 16, 1902, at Ceiba, Honduras, is the southernmost record 

 of this species with which I am familiar. This was perhaps a winter 

 straggler. 



