.--The Green-tailed Towhee, currently placed in the genus Chlorura Sclater, 1862, was originally described by Audubon (1839). The twenty-second supplement (1947) to the American Ornithologists' Union Check-List of North American birds designates the species as Chlorura chlorura (Audubon). The species breeds from central Oregon and south- central Montana to southern California, southeastern New Mexico, and central western Texas. In general it is a bird of the mountains or, in the Great Basin, of high plateau country. The purpose of the present paper is to present evidence to show that this species is a true Pipilo allied to the type species, Pipilo erythroph- thalmus, by way of the closely related Pipilo ocai, the Collared Towhee, of Mexico. Few species of North American birds have been moved about generically more than the Green-tailed Towhee. Ridgway (1901: 401-402) lists eight genera in the synonymy of the species and there have been two others in use since 1901. The species appeared most frequently in the literature under Pipilo prior to 1896 when Ridgway placed it in a new monotypic genus, Oreospiza. He proposed this separation in spite of his remarks favoring it as a Pipilo, which appeared in 1890 in a review of a work by Salvin and Godman. Salvin and Godman (1879-1887) had placed the species in Embernagra, and Ridgway correctly pointed out the line of relationship to the true towhees via the rufous-capped Mexican forms currently known as P. ocai. The original use of the genus Oreospiza for the Green-tailed Towhee appears on page 439 of Ridgway's "Manual" (1896), and in the appendix (1896: 605) he writes as follows: "Page 439, Pipilo ohiorufus (=Oreospiza chlorura): This bird, which has been referred by different authors to the genera "Embernagra" (i.e. Arremonops) and Atlapetes, but which is really far more out of place in either than in Pipilo, I propose to make the type of a new genus, Oreospiza, whose characters are intermediate between, or rather a combination of, those of Pipilo and Zonotrichia." This constitutes the original description of the genus. Five years later Ridgway (1901: 399) wrote the following: "Oreospiga is inter- mediate between Pipilo and Zonotrichia, though much nearer the former, with which it agrees in its stout feet with long claws, rounded tail, and form of bill. Its coloration, too, is not so abnormal for Pipilo as has been supposed, every feature of color--rufous cap, white throat, yellow carpal edge, and olive-green upper parts-- being shared by some species of that genus, though by none in the stone conbination. The wing, however, is very different from that of Pipilo, being quite the same in the relative length of the primaries as that of Zonotrichia, that of Z. albicollis being even more rounded." In the statement quoted above with reference to color features, Ridgway's remark that the rufous cap and other color characters are, "shared . .., though by none in the same combination," is simply in error. Pipilo ocai combines these and other color characters also found in the Green-tailed Towbee. It thus seems that Ridg- way's only remaining basis for separation is that of wing shape which, in the Green- tailed Towbee, is longer and more pointed than in Pipilo ocai and P. erythrophthalmus. Long, pointed wings are characteristic of species which are strong flyers or which make long migratory flights. Mayr (1942: 92, 95) discusses the correlation between wing length and geographic distribution and points out that forms of cooler climates tend (1) to have longer wings and (2) to be more migratory than forms of warmer climates. The Green-tailed Towbee is migratory, and it seems apparent that the relatively longer wing is correlated with this habit. Further changes in the generic position of the Green-tailed Towbee, following Ridgway's description of Oreospiza, have been dictated solely by nomenclatural problems. In 1915 Richmond proposed the genus Oberholseria to replace Oreospiza Ridgway, 1896, because the latter was preoccupied by Oreospiza Keitel, 1857. The change to Chlorura Sclater, 1862, was effected in 1947, as noted above, since Chlorurus Swainson, 1839, was deemed not to preoccupy Sclater's name. In view of the foregoing it can scarcely be argued that the basis for Oreospiza Ridgway is entirely beyond question. It now remains to present the evidence in favor of its inclusion with the true towhees in the genus Pipilo. In two recent papers (1950; 1954) I have described the extensive hybridization which occurs in Mexico between Pipilo erythrophthalmus and Pipilo ocai. Nearly 1,500 specimens showing evidence of hybridization between these two species have been examined up to the present. The two species are strikingly different in color pattern (1950: plate 11), and P. ocai is approximately 30 per cent heavier in weight than P. erythrophthalmus. Moreover, these species show well-marked, but over- lapping, ecological differences (1950: 152-153; 1954: 270-273). Their songs, although similar, are easily distinguished, but the common call notes of the two are easily confused. Their eggs are alike in color and pattern, and both build similar nests. Both are species of dense underbrush and both scratch in the leaf litter in the same manner. P. ocai is primarily a bird of the understory vegetation at the higher elevations where the dominant trees are conifers. P. erythrophthalmus occurs most abundantly in the brushy thickets at lower elevations where oaks are more frequently dominant. Hybridization occurs at some of the points where the two species come into contact. The situation concerning the degree of relationship between ocai and erythroph- thalmus is relevant here in order to establish beyond any doubt that these two are properly considered congeneric. If this be granted then it remains only to demon- strate the close relationship between P. ocai and the Green-tailed Towbee in order to show the latter also to be a Pipilo. In color pattern the Green-tailed Towbee is far more similar to P. ocai than the latter is to/. erythrophthalmus. The Green-tailed Towbee looks like a diminutive edition of ocai with the breast and facial areas gray rather than black. If size alone is considered of importance it may be pointed out that one race of/. erythrophthalmus, the Socorro Island population,/. e. carmani, is smaller than the Green-tailed Towbee. The ecological preferences of the Collared and Green-tailed towhees are extremely similar. Both occur in dense brushy vegetation, and in many parts of its range the Green-tailed occupies the shrubby undergrowth associated with conifers. The songs of the two species are recognizably different but show a remarkably similar pattern. After becoming familiar with the song of/. ocai at many localities in Mexico in 1946 and 1948, I heard the song of the Green-tailed Towbee near Irwin, Bonneville County, Idaho, on July 10, 1949. The similarity in the two songs was striking. The call notes are even more alike. Both utter a roewing note which may be written, "zree" or "zew." This cat-like note is also characteristic of many races of /. erythrophthalmus, especially the "Spotted Towbees" of the western United States and Mexico. In coloration and pattern of markings, the eggs of /. erythrophthalmus, J>. ocai, and the Green-tailed Towbee are nearly identical. All of these species lay eggs which have a whitish ground color with reddish markings. The evidence presented above contains many points in favor of including the Greea-tailed Towbee in J>ipilo, but there is another line of reasoning which, although negative, bears on the question. The so-called brown towbees, lipilo fuscus, rutilis, and aberti, are probably not so closely allied to/. erythrophthalmus as is the Green-tailed Towbee. Davis (1951: 100-102) suggests that the brown towbees may be more closely related to the genus Melozone and not congeneric with the red-eyed towbees, ocai and erythrophthalmus. I am in agreement with Davis on this point and propose, as a first step toward the correct generic alignment of these various forms, that the Green-tailed Towbee be recognized as a true J>ipilo. If one is to disagree with this proposal he must justify the inclusion of the brown towbees in J>ipilo because they are without doubt less closely related to the type species, Pipilo erythrophthalmus, than is the Green-tailed Towbee. The name of the Green-tailed Towbee becomes Pipilo chlorurus (Audubon) if this recommendation is accepted. LITERATURE CITED AMERICAN ORNITHOLOGISTS' UNION. 1947. Twenty-second supplement to the American Ornithologists' Union check-list of North American birds. Auk, 64: 445-452. AUDUBON, J.j. 1839. Ornithological Biography, vol. 5. (Edinburgh.) DAvis, J. 1951. Distribution and variation of the brown towbees. Univ. Calif. Publ. Zool., 52: 1-120. KEITE, G.T. 1857. Verzeichniss der EuropSischen V6gel .... (etc.) (Berlin.) MAYR, E. 1942. Systematics and the origin of species. (New York, Columbia Univ. Press), 334 pp. RICHMOND, C. W. 1915. Notes on several preoccupied generic names (Aves). Proc. Biol. Soc. Wash., 28: 180. RIDGWA3/4, R. 1890. Review of Salvin and Godman's Biologia Centrali-Americana: Aves. Auk, 7: 189-195. RIDGWA3/4, R. 1896. Manual of North American birds. Second edition. (Phila- delphia, J. B. Lippincott), 653 pp. RmGw,3/4, R. 1901. The birds of North and Middle America. Bull. U.S. Nat. Mus., 50, part 1: xxx q- 715 pp. S,w, O., and F. D. GoDM,. 1879-1887. Biologia Centrali-Americana. Aves. Vol. 1 (London) xliv q- 512 pp. Sc,xR, P. L. 1862. Catalogue of a collection of American birds. (London), xvi q- 338, 20 pls. SB3/4, C.G. 1950. Species formation in the red-eyed towhees of Mexico. Univ. Calif. Publ. Zool., 50: 109-194. SmokY, C.G. 1954. Hybridization in the red-eyed towhees of Mexico. Evolution, 8: 252-290. 8WAINSON, W. 1839. On the natural history and classification of fishes, amphibians and reptiles. (London). CAm,r:s G. Smr:3/4, Department of Conservation, Cornell University, Ithaca, New York.