_Characters._--Adult: Long-tailed sea bird white with pinkish tint except for black lores and eye streak; black shafts on feathers of secondaries, flanks, and tail coverts; black bases on feathers of head; central tail feathers elongate with black shafts and bright red webs; bill orange-red with black nasal streak; tarsus and foot bluish-yellow, distal part blackish. Immature: Resembles adult but barred with black above; bill blackish. _Measurements._--Yamashina (1940:676) lists the measurements for seven adult birds from Maug in the northern Marianas as wing 304-319 and exposed culmen 55-62. _Nesting._--Yamashina (1932a:406) reports the taking of one egg at Pagan in the Marianas on February 15, 1931. _Remarks._--The Red-tailed Tropic Bird has been recorded from the Mariana, Caroline, and Marshall Islands. On the basis of our present knowledge it appears to be uncommon in most of Micronesia and may be established as a resident bird only in the northern Marianas, as shown by Yamashina (1932a:406 and 1940:676), Coultas obtained an immature male at 3° N and 158° E, which is at a point in the ocean south of the eastern Carolines. Possibly this bird and others obtained in the Carolines are representatives of the subspecies, _P. r. melanorhynchos_ Gmelin, which is known from the Palmerston, Society and Turtle islands. =Phaëthon lepturus dorotheae= Mathews White-tailed Tropic Bird _Phoethon lepturus dorotheae_ Mathews, Austr. Avium. Rec., 2, 1913, p. 7. (Type locality, Queensland.) _Phaeton candidus_ Kittlitiz, Denkw. Reise russ. Amer. Micron. und Kamchat., 1, 1858, p. 382 (Ualan); Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 9, 118 (Pelew); Finsch, Journ. f. Ornith., 1872, p. 57 (Pelew); Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 90, 114 (Pelew, Ualan); Finsch, Journ. Mus. Godeffroy, 1875, pp. 6, 47 (Palau); _idem_, Proc. Zool. Soc. London, 1877 (1878), p. 782 (Ponapé); _idem_, Journ. f. Ornith., 1880, pp. 296, 309 (Ponapé, Kuschai); _idem_, Proc. Zool. Soc. London, 1880, p. 577 (Ruk); Schmeltz and Krause, Ethnogr. Abth. Mus., Godeffroy, 1881, pp. 281, 299, 330, 353 (Ponapé, Mortlock, Nukuor, Ruk); Finsch, Mitth. Ornith. Ver. Wien, 1884, p. 52 (Kuschai); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 73 (Pelew, Ruk, Luganor, Nukuor, Ponapé, Ualan, Marshalls); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 62 (Agrigan, Palaos, Ruk, Kushai, Marshalls); Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne). _Phaeton flavirostris_ Finsch, Ibis, 1880, pp. 329, 333 (Ratak Chain); _idem_, Ibis, 1881, pp. 105, 109, 115 (Kuschai, Ponapé).