6io Field Museum of Natural History — Zoology, Vol. IX. 



wing coverts and tail, black, more or less marked with white; 

 the primaries and outer tail feathers, heavily marked with white; 

 rump, white; upper tail coverts, black, tipped with white; bill, 

 brownish white. 



Adult female: Under wing, coverts, bright safifron-yellow ; upper 

 parts, grayish brown, streaked with dusky brown and more or less 

 tinged with olive brown on the rump; crown and sides of head, dark 

 grayish brown, a whitish streak in centre of crown and a white super- 

 ciliary stripe; wings and tail, grayish brown; wing coverts, tipped 

 with white; throat, breast and sides of body, tinged with pale bufl 

 and streaked with dusky; belly, whitish. 



Length, about 8; wing, 4; tail, 3; bill, .65. 



This beautiful species is a common summer resident in northern 

 Illinois and Wisconsin, and occurs during migrations in southern 

 Illinois. It is one of the most beautiful of our birds and of special 

 value to the agriculturist as, besides other insects, it eats the potato 

 beetle. The male is one of our most gifted songsters, its delight- 

 ful warble being varied and very sweet. 



It breeds in May and June. The nest is in bushes or low trees 

 and is composed of rootlets and dry stalks of weeds, etc. The eggs 

 are from 3 to 4, rarely 5, pale greenish blue or bluish green, marked 

 and speckled with various shades of brown, and measure about .96 

 X .67 inches. 



Genus GUIRACA Swainson. 



275. Guiraca caerulea (Linn.). 



Blue Grosbeak. 



Distr.: Eastern United States, southern Illinois, Nebraska and 

 southern New Jersey to Florida and the Gulf states, south in winter 

 to Cuba and eastern Mexico (Yucatan) ; breeds throughout its 

 United States range. 



Adult male: General plumage, dark blue; chin and region about 

 base of bill, black; wings and tail, blackish brown; middle and 

 greater wing coverts, tipped with chestnut, forming wing bars. 

 (In assuming adult plumage the feathers of the back are edged with 

 chestnut, and the feathers of under parts narrowly edged with 

 whitish). 



Adult female: Upper parts, brown, the head, clear brown, shading 

 to grayish brown on the rump; under parts, buffy brown, palest on 

 throat and belly; wing and tail, grayish brown, the greater and 

 middle wing coverts, edged and tipped with tawny brown. 



