Vol. XIV 
tea OBERHOLSER on a New Marsh Wren. 187 
from the intermediate region belong to an apparently undescribed 
geographical race. 
Considered with reference to its western representatives Aalus- 
tris presents the extreme of darkness and richness in the colora- 
tion of the upper parts and flanks. The Pacific Coast bird is, 
however, nearly as dark above, though the colors are duller; but 
the form from the Great Basin is paler than either. In palustris 
the lower parts are usually clearer white, the bill averages longer, 
the, wings and tail shorter than in either of the western races. 
The eastern bird further differs in having the middle tail-feathers 
usually without regular or distinct bars, the upper and lower tail- 
coverts not barred; but no one of these characters is quite 
constant. In most examples of palustris (go per cent of the 
specimens examined) the markings of the central rectrices are 
reduced to mere spots or scarcely indicated bars, being rarely so 
regular or so clearly defined as in extreme examples of the western 
races. In 94 per cent of the available specimens of fa/ustris the 
superior tail-coverts are found to be without appreciable transverse 
markings; while the remaining 6 per cent exhibit fairly well 
defined bars. The absence of distinct bars on the lower tail- 
coverts serves to distinguish 71 per cent of the specimens 
examined, and is apparently a fair average character, though 
some of the remaining 29 per cent have these markings fully as 
dark and as clearly indicated as in the most typical examples of 
the western forms. 
Professor Baird, in distinguishing ! palustris from his jaludicola 
says of the former, “bill lengthened, equal to tarsus’’; but 
reference to the measurements given in the present paper will at 
once show the fallibility of this character. 
Fall specimens of fa/ustris are, as a rule, noticeably darker and 
more richly colored than those taken in spring or summer, this 
affecting chiefly the brown portions of the plumage; but in this 
respect there is at all seasons considerable individual variation. 
Among the specimens at hand, most of them from Illinois and 
from the vicinity of Washington, D. C., much difference exists in 
the amount of paler color on the pileum. This lighter brown 
1 Review of American Birds, I, 1864, 148. 
