THIE Santa Rita Bush-tit (Psaltrihparus santaritw) was described by Ridgway (Proc. U. S. Nat. Mus., X, 1888, p. 697) and remained for some years in good standing in the American Ornithologists' Union Check-List, as a species occurring in, and limited to, the Santa Rita Mountains, Arizona. The principal characteristic of the supposed species, as distinguished from P. plumbeus, was the presence of a dusky line on the sides of the head, over the auriculars. During several seasons collecting in southern Arizona the writer collected a fairly extensive series of bush-tits, keeping a careful lookout for P. santaritl, which, however, for some time he failed to find. Finally, in the summer of 1903, specimens were taken in the Santa Rita Mountains which answered the description, but they proved to be birds in juvenal plumage. In one or two instances adults, obviously in attendance upon these young birds, were collected, and these proved to be plumbeus; in other cases flocks from which examples of santaritce were secured, were carefully scrutinized without revealing the presence of any individuals with black head markings. Altogether the writer felt convinced that the supposed Santa Rita Bush-tit was in reality the immature plumage of P. plumbeus, and so stated in a paper on the birds of the Santa Rita Mountains (Condor, 7, 1905, p. 81). In the meantime Mr. Oberholser had published a synopsis of the genus Psaltriparus (Auk, XX, 1903, pp. 198-201), in which he made the following statement (p. 200) in regard to the disputed species. The type of Mr. Ridgway's Psaltriparus santarita? is an immature male of lloydi, as a careful examination shows, and it can be easily matched by young male specimens from any part of the range of the latter. In accordance with this idea the third (1912) edition of the A. 0. U. Check-List (p. 353) gives the range of Psaltriparus melanotis lloydi as including southeastern Arizona, presumably upon Oberholser's statement quoted above.