Empidonax Traillii alnorum - Notes on Certain Flycatchers of the Genus Empidonax. by Wm B Brewster. Empidonax traillii alnorum, new subspecies. ALDER FLY- CATCHER. Auk, XII, Apr., 1895, pp. 161-3. 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. Hence 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 42nd parallel of latitude, and from North America at large west of the Plains, including skins from Fort Resolution on Great Slave