Nelson North American Mainland Myiarchus. 41 



gua (Ometepe, San Juan del Sur); Mexico (Tonala, Chiapas). Not mi 

 gratory. 



Zonal distribution, Arid and Semi- Arid Tropical. 



Specific characters, Generally similar to M. nuttingi but larger and 

 heavier with much stouter, heavier bill and proportionately shorter 

 tail. 



Description of fresh plumage. Crown dark olive shaded with greenish 

 and a slight buffy suffusion on borders of feathers in some specimens; 

 back lighter olive with a greenish shade (latter nearly or quite absent 

 in worn plumage); back of neck sometimes a little grayer than back; 

 upper tail coverts dark broccoli brown edged and sometimes suffused 

 throughout with dark rusty rufous; primaries, except first one, edged 

 along middle with dark rufous; wing coverts and tertials edged with 

 dull whitish or brownish white with shade of greenish on coverts in 

 some specimens; outer web of outer tail feather pale drab; inner web 

 uniform rufous, sometimes with a narrow inconspicuous line of dusky 

 along shaft; other tail feathers, except middle pair, similar; chin, neck 

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

 deep primrose yellow. 



Measureme7its. Averages of two adult males: wing, 96 (93-99); tail, 

 86 (85-87); culmen, 21 (21); tarsus, 23.5 (23-24). 



Averages of five adult females: wing, 94.4 (93-96); tail, 85.2 (8.1-87); 

 culmen, 20.7 (19.5-21); tarsus, 22.6 (22-23). 



General notes. In general coloration this species differs but slightly 

 from M. nuttingi but may be easily distinguished by differences in size 

 and proportion, and especially by the much larger bill, and more rusty 

 upper tail coverts, Although resembling crinitus somewhat in size and 

 pattern of color on outer tail feathers yet the much paler colors above 

 and below readily distinguish them from that species. Like other 

 members of the genus this species gradually fades in spring until the 

 upper parts lose the greenish cast and become dull olive brown. 



Myiarchus yucatanensis Lawrence. 



YUCATAN CHESTED FLYCATCHER. 



1871. Myiarchus yucatanensis Lawrence, Proc. Acad. Nat. Sci. Phila., 

 1871, p. 235. Based on the Myiarchus mexicanus Lawrence (nee 

 Kaup) Ann. Lye. Nat. Hist. N. Y., IX, p. 202, June, 1869. 



Type locality. Merida, Yucatan. Type in American Museum of 

 Natural History (Lawrence Collection). 



Breeding range. Peninsula of Yucatan and Cozumel Island. Not 

 migratory. 



Zonal distribution. Arid or Semi-Arid Tropical. 



Specific characters. Crown bistre brown; upper tail coverts hair 

 brown, slightly if at all edged with russet; inner webs of all but middle 



