84 PROCEEDINGS OF THE ACADEMY OF 



Hist. N. Am. B., 232): Similar to the young male; feathers of 

 back, etc., less broadly margined with rusty. Ochraceous wash 

 on lower parts more decided; stripes beneath broader and less 

 lanceolate; on the sides broadly ovate, and on the flanks in form 

 of broad transverse bars; tibia? more thickly spotted transversely; 

 lower tail-coverts immaculate. Wing, 9.00 ; tail, 7.80 ; tarsus, 2.25 ; 

 middle toe, 2.50. Fourth quill longest; third shorter than fifth ; 

 second intermediate between sixth and seventh; first, 2.90 shorter 

 than longest. Graduation of tail, .90. 



Although occasional individuals from Mexico lead at first to the 

 impression of a decided difference from the usual st} T le of the 

 eastern United States, the}'' lose their apparently distinctive feat- 

 ures when a large series is brought together for comparison. As 

 a rule, adult males from Mexico agree with each other, and differ 

 from the average style of the same plumage in birds from the 

 eastern United States, in having the rufous of the lower parts in 

 greater amount in proportion to the white, that of the tibiae being 

 often almost unbroken; there is usually also less of concealed 

 white on the scapulars. The most typical example of the so- 

 called A. mexicanus, however, is one from Massachusetts, de- 

 scribed on p. 81. The climatic difference between eastern and 

 western birds of this species is more marked in the } - oung than in 

 the adult plumage, however; and there seems to be great con- 

 stancy in the differences observable. Thus, the western birds are 

 darker colored throughout, the brown markings occupying larger 

 areas, and the white portions of a less pure color, being more or 

 less suffused, or stained with pale ochraceous. The markings on 

 the tibia? are almost always transversely-cordate spots instead of 

 longitudinal streaks. This darker style of plumage is character- 

 istic of the entire Western Province, east to the Missouri Plains ; 

 but along the southern border and in Mexico, birds more like the 

 eastern style seem to prevail. 



Upon the whole, it is found impossible to characterize by tan- 

 gible, and, at the same time, constant characters, two geographical 

 races of this species ; for, while a barely appreciable difference 

 characterizes the majority of the birds of either region, the cases 

 of individuals which correspond in every particular being found 

 in the region of which the}' are not typical are too numerous to 

 warrant the consideration of the two extremes as strictly climatic. 

 It remains, therefore, for us to better class these variations as of 



