48 Nelson — North American Mainland Myiarchus. 



Myiarchus lawrencei olivascens Ridgway. 



OLIVACEOUS FLYCATCHER. 



1884. Myiarchus lawrencei olivascens Ridgway, Proc. Biol. Soc. Wash., 

 II, p. 91. 



Type locality. — Santa Efigenia, Oaxaca. Type No. 57,655 U. S. National 

 Museum. 



Breeding range. — Southern Arizona and thence south in western Mex- 

 ico, west of the Sierra Madre to northern Tepic. 



Migrates from northern part of its range south throughout southwest- 

 ern Mexico to Chiapas and inland through Michoacan and Guerrero. 

 Resident in southern part of breeding range. 



Zonal distribution. — Lower Sonoran and Arid Tropical. 



Buhspecific characters. — Decidedly smaller than true lawrencei; upper 

 parts grayer and rectrices only slightly if at all edged with pale cinna- 

 mon. 



Description of fresh plumage. — Crown olive brown, but slightly darker 

 than back; back grayish olive with but slight if any indication of green- 

 ish: upper tail coverts hair brown usually but not always edged with 

 pale cinnamon; outer edges of tail leathers, secondaries and all but two 

 outer primaries edged with slightly darker shade of cinnamon; wing 

 coverts vary from drab to Isabella color; inner webs of inner tail 

 feathers usually plain dusky but sometimes with a slight buffy edge 

 along inner border; chin, throat and breast ashy gray; abdomen and 

 under tail coverts varying from sulphur yellow to straw yellow. 



Measurements of specimens from soutJiern Arizona: — Averages of ten 

 adult males: Wing, 81.5 (76-85); tail, 77.9 (73-81); culmen. 16.6 (16-17): 

 tarsus, 18.9 (18-20). 



Averages of ten adult females: Wing, 76.4 (75-78); tail, 72.5 (70-75); 

 culmen, 16.1 (15-17); tarsus, 18.1 (17.5-19). 



General notes. — The type of olivascens came from Santa Efigenia, 

 Oaxaca, close to the border of Chiapas, where the resident birds are 

 nearly typical lawrencei both in size and color. The type of olivascens is 

 in winter plumage and agrees in every way with birds from northwestern 

 Mexico and southern Arizonia. From this it is practically certain that 

 this individual was a winter visitant from the north. The birds of 

 southern Arizona may be considered typical of the form. 



M. olivascens is apparently not numerous in winter south of Guerrero. 

 The Bangs collection contains one specimen taken on April 4, at 

 Patzcuaro, Michoacan, which was probably a migrant. Among a series 

 of over fifty specimens at hand only a few have indications of a buffy 

 border along the inner edge of the tail feathers, and most of these are 

 intergrades from along the southern border of its range where it merges 

 into querulus. There is also a gradual increase southward in size. 



