23d 
U. S. P. R. R, EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
PARULA AMERICANA, Bonap. 
Blue Yellow-backed Warbler. 
Parus amcricanus, Linnaeus, Syst. Nat. ed. 10, I, 1758, 190.— Gm. Syst. Nat. I, 1788, 1007.— Lath. Ind.Orn. II, 
1790, 571. 
Motacilla americana, Gmelin, Syst. Nat. I, 1788, 960. 
Sylvia americana, Latham, Ind. Orn. II, 1790, 520.— HoNAr. Syn. 1828, 33.— Aud. Orn. Biog. I, 1832, 78 ; pi. 15. 
Sylviccla americana, Rich. List, 1837.— Aud. Syn. 1839, 59.— Iu. Birds Amer. II, 1841, 57 ; pi. 91. 
Parula americana, Bonap. List, 1838.— 1b. Consp. 1850, 310.— Gosse, Jamaica, 1847, 154. 
Compsothlypis americana, Cabanis, Mus. Hein. 1850, 20, (Type.) 
Ficedula ludoviciana, Brisson, Orn. Ill, 1760, 500 ; pi. xxvi. 
Motacilla ludoviciana, Gmelin, Syst. Nat. I, 1788, 983. 
Motacilla eques, Boddaert, Tabl. pi. enl. 1783, (Gray.) 
Sylvia torquata, Vieillot, Ois. Am. Sept. II, 1807, 38 ; pi. xeix. 
Thryothorus torquata, Stephens, Shaw Zool. XIV, i, 1826, 194. 
Sylvia pusilla, Wilson, Am. Orn. IV, 1811, 17 ; pi. xxviii. 
Sylvicola pusilla, Swainson, Zool. Jour. Ill, 1827, 169. (Type of genus.) 
Buffon, PI. enl. 731, f. 1 ; 709, f. 1. (?) 
Sp. Ch.—A bove blue, the middle of the back with a patch of yellowish green. Beneath yellow anteriorly, white behind. 
A reddish brown tinge across the breast. Lores and space round the eye dusky ; a small white spot on either eyelid ; sides of 
head and neck like the crown. Two conspicuous white bands on the wings. Outer two tail feathers with a conspicuous spot 
of white. Female similar, with less brown on the breast. Length, 4.75; wing, 2.34 ; tail, 1.90. 
IJab. —Eastern North America to the Missouri ; south to Guatemala. 
Male in spring. —Upper parts, scapulars, sides of the neck and head, edges of the quills 
and tail feathers bluish ash. A triangular spot of yellowish green between the wings ; (this 
i s slightly tinged in the middle of each feather with reddish brown.) The tips of the bluish 
feathers above very faintly tipped with greenish yellow, indicating the changes in the fall. 
Lore dusky; a spot on the upper and under eyelids white. Individuals differ in the coloring 
of the throat. In one the chin is yellowish ; across the throat a band of dark reddish brown ; 
each feather tipped and edged with yellow. Fore part of the breast lighter reddish brown, 
approximating to chestnut, this on a ground of yellow ; sides of the breast also with traces of 
this chestnut. In another individual the dusky of the throat is extended more towards the 
chin, and more decided. Sides under the wing light bluish ash. Traces of reddish brown under 
the edge of the wing when closed. Abdomen, lower coverts, and vent white, with occasional 
traces of pale yellow. Two broad hands of white on the wings. Large patch of white on the 
inner webs of the outer two feathers near the end ; on the third a white spot on the inner vane, 
and the inner edge of this and the two next margined with the same. Feet dusky ; upper 
mandible dark brown, lower yellowish. 
Female in spring. —Upper parts similar to the male ; white bands on the wings somewhat 
narrower. Two specimens differ in the color beneath. One specimen is very similar to the 
male, with the dark reddish brown across the throat very decided. Lores also blackish. This 
specimen (No. 628) is marked “female;” it may possibly be male. Another, certainly a 
female, No. 338, has the throat, chin, and fore part of breast yellowish, very faintly tinted 
with brownish red across the throat. Lores not dusky ; eyelids faintly white. Tail with less 
white, and wanting the white spot on the third feather. 
Male in fall. —Similar generally to the male in spring. Chin tinged with brownish ; more 
