f 
Empidonax traillii alnorum, new subspecies. Alder Fly- 
Subspec. char .— Differing from E. traillii (i. e., E. “ pusillus" of Baird 
and subsequent authors) in having the coloring of the upper parts richer 
and more olivaceous, the wing bands yellower and hence more conspicu¬ 
ous, the bill decidedly smaller and the legs rather shorter. Type No. 1367, 
collection W. B., $ ad., Upton, Maine, June 3, 1872. 
There is of course nothing new about this separation or the 
characters on which it is based. Indeed, all of the latter — as 
21 
Baird apparently did not have the Audubonian specimens before 
him when he made the comparison of traillii and pusillus above 
referred to. At least he does not allude to them in the text nor 
are they included in his tabular lists. The series of what he con¬ 
sidered to be true ■traillii comprised nine examples, of which one 
came from New Hampshire, seven from Carlisle, Pennsylvania, 
and one from Mexico. The Carlisle birds were all taken in May 
and were unquestionably migrants on their way to northern New 
England or New York. Plence it is evident that his impressions 
of traillii were based on material which did not really represent 
that bird. 
I must confess to • a certain sense of relief that, as has been 
just shown, the responsibility for the above separation rests 
mainly on shoulders other and broader than mine; for while I 
honestly believe it to be based on intrinsically sound characters, 
the differences between the two birds in question are, after all, 
so slight and so difficult of verification without the aid of large 
series of specimens for comparison that the identification of 
individual specimens by descriptions alone is an almost hopeless 
task. This, however, is by no means a novel condition among 
Empidonaces, for this puzzling group includes several forms which 
are positively known to be distinct species, but which in the 
dried skins cannot always be distinguished with either ease or 
certainty. 
The respective breeding ranges of E. traillii and E. t. alnorum 
cannot be mapped at present with entire precision, but I have had 
no hesitation in referring to the former all the breeding specimens 
that I have examined from the Mississippi Valley south of the 
42 nd parallel of latitude, and from North America at large west 
of the Plains, including skins from Fort Resolution on Great Slave 
