672 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. IX. 



tinged with pale brown ; bend of wing, yellow ; no wing bars ; no 

 white on tail. 



Adult male in fall: Similar, but feathers of black mask tipped 

 with gray; back and sides browner. 



Adult female in summer: No black mask on head; forehead more 

 or less tinged with brown; sides of head grayish olive; under parts 

 much paler yellow, shading to whitish on belly; otherwise similar to 

 adult male. 



Immature in fall: The male has the dark mask only partially 

 developed and often merely indicated by dusky; sides more strongly 

 tinged with buffy brown. The female has the under parts strongly 

 tinged with buff, shading to brownish on the sides and flanks. 



Length, 4.85; wing, 2.20; tail, 2.10; bill, .40. 



The Maryland Yellow-throat is a very common summer resident 

 in Illinois and Wisconsin, where it frequents thickets and bushes. 



Breeds in May and June. The nest is on or near the ground, cup- 

 shaped and composed of shreds of bark, leaves, and grass. The eggs 

 are 4 or 5, pure white, speckled with dull rufous and dark brown 

 chiefly at the larger end, and measure about .71 x .53 inches. 



The note is clear and comparatively loud. Mr. Frank M. Chapman 

 happily suggests that the song of this bird be written "7 beseech you, 

 I beseech you, I beseech you, I beseech you." It varies considerably 

 however, and at times resembles we-chee-chu repeated several times 

 with the accent on the first instead of the third syllable. 



Geothlypis trichas brachidactyla (Swainson) is no longer recognized 

 as separable from G. trichas. 



Genus ICTERIA Vieill. 



333. Icteria virens (LINN.). 

 YELLOW-BREASTED CHAT. 



Distr.: Eastern United States, west to the Dakotas, Kansas, and 

 eastern Texas, north to southern Ontario, southern New England, 

 southern Wisconsin, and southern Minnesota , breeding throughout 

 its United States range; winters in eastern Mexico and Central 

 America to Costa Rica. 



Adult: Strikingly different in size and appearance, from all other 

 local species, belonging to this family.* Upper plumage, bright 



*Since the monotypic genus Icteria was placed in the family Mniotiltidae 

 by Professor Baird in 1858, his view in the matter has been generally accepted 

 by Ornithologists (albeit in some cases with more or less hesitation) as being 

 the best way out of a rather difficult problem. 



