BIRDS OF NORTH AND MIDDLE AMERICA, 5-17 



i. Tail even or slightly double-rounded; larger (male averaging wing 

 more than 70, tail more than 57, exposed culmen 12 or more). 

 {Empidonax traillii.) 

 j. Above duller or browner oli^■e; wing-liands darker; wing and 

 tail averaging t;lightly shorter, Inll deei<ledly larger (male 

 averaging wing 70.6, tail 57.8, exposed culmen 13; female, fiG, 

 55.7, 12). (Western North America, south in winter to north- 

 ern South America.) Empidonax traillii traillii (p. 555) 



jj. Above clearer or more greenish olive; wing-bands paler; wing 

 and tail averaging slightly longer, bill decidedly smaller 

 (male averaging wing 71.8, tail 58.4, exposed culmen 12; 

 female, 68.4, 55.4, 11.7). (Eastern and northern North 

 America, south in winter to western Ecuador.) 



Empidonax traillii alnorum (p. 558) 



ii. Tail slighllybut decidedly emarginated; smaller (male averaging 



wing 64.2, tail 54.3, exposed culmen 10.7; female, 60.9, 52.5, 



10.5). (Eastern North America, south in winter to Panama.) 



Empidonax minimus (p. 561) 



//'. Exposed culmen shorter than middle toe, without claw; bill narrower, 



its width at anterior end of nostrils decidedly less than half the length 



of exposed culmen. (Western North America, south in winter to 



Guatemala.) Empidonax hammondii (p. 565) 



ee. Tenth (outermost) primary shorter than fifth (sometimes shorter than 

 fourth) . 

 /. Bill narrower, its width at anterior end of nostrils less than half the length 

 of exposed culmen. 

 g. Under parts whitish, at least on throat. 



h. Above olive; posterior nnder parts distinctly pale yellow; smaller 

 (male averaging wing 69. 5, tail 62.6, exposed culmen 12; female, 

 67.4, 60.6, 11.9). (Western United States, south in winter to 



Southern Mexico.) Empidonax wrightii (p. 567) 



hh. Above grayish olive (becoming gray on pileum); posterior under 

 parts yellowish white; larger (male averaging wing 72.6, tail 60.8, 

 exposed culmen 12.9; female, 69.1, 58.9, 12.9). (Southern Cali- 

 fornia and Lower California to New Mexico and Colorado, south to 



central Mexico.) Empidonax griseus (p. 570) 



gg. Under parts distinctly yellowish (the throat sometimes pale gi'ayish.) 

 h. Bill narrower, its width at anterior end of nostrils less than 5 mm. 

 i. Above clearer or less brownish olive. 

 j. Much paler olive above; chin and throat pale yellowish or yel- 

 lowish white; larger (male averaging wing 77.4, tail 66.1; 

 female, 72.5, 62). (Northwestern Mexico.) 



Empidonax pulverius (p. 572). 

 jj. Much darker olive above; chin and throat tU'cked or suffused 

 with dusky; smaller (male averaging wing 73.8, tail 64.5; 

 female, 69.4, 59.1). (Northeastern to southern ilexico.) 



Empidonax trepidus (p. 575) 

 a. Alwve more brownish olive (mah' averaging wing 73.2, tail 62). 



(Eastern Mexico.) Empidonax fulvipectus (p. 573) 



hh. Bill broader, its width at anterior end of nostrils 5-6 mm. {Empi- 

 dona.v dijjicilis.) 

 i. Coloration paler and duller, the upper parts less decidedly olive- 

 greenish, the under parts less strongly yellowish; bill more 

 tapering terminally, with lateral outlines more nearly straight. 



