Monarcha rugensis Hartlaub, Archiv. f. Naturgesch., 18, 1852, p. 133 (Gruppe Roug. = Truk); idem, Journ. f. Ornith., 1854, p. 168 (Carolinen = Truk); idem, Proc. Zool. Soc. London, 1867 (1868), p. 829 (Hogoleu = Truk); Gray, Hand-list Birds, 1, 1869, p. 321 (Caroline = Truk); Giebel, Thes. Ornith., 2, 1875, p. 614 (Carolinae = Truk); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 353 (Ruk).
Colluricincla rugensis Pucheran, Voy. Pôle Sud, Zool., 3, 1853, p. 62 (Ruk); Hartlaub, Journ. f. Ornith., 1854, p. 162 (Roug = Truk).
Metabolus rugensis Bonaparte, Comptes Rendus Acad. Sci. Paris, 38, 1854, p. 650 (no locality = Truk); Sharpe, Cat. Birds British Mus., 4, 1879, p. 238 (Ruk); Finsch, Proc. Zool. Soc. London, 1880, p. 575 (Ruk); Tristram, Cat. Birds, 1889, p. 197 (Ruk); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 19 (Ruk); Nehrkorn, Kat. Eiers., 1899, p. 26 (Ruk); Hartert, Novit. Zool., 7, 1900, p. 4 (Ruk); Matschie, Journ. f. Ornith., 1901, p. 112 (Ruk); Reichenow, Die Vögel, 2, 1914, p. 262 (Karolinen = Truk); Takatsukasa and Kuroda, Tori, 1, 1915, p. 54 (Ruk); Wetmore, in Townsend and Wetmore, Bull. Mus. Comp. Zool., 63, 1919, p. 203 (Truk); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 63 (Ruk); Mathews, Syst. Avium Australasianarum, 2, 1930, p. 470 (Ruk); Yamashina, Tori, 7, 1932, p. 404 (Truk); Hand-list Japanese Birds, rev., 1932, p. 178 (Truk); Hand-list Japanese Birds, 3d ed., 1942, p. 197 (Truk); Mayr, Birds Southwest Pacific, 1945, p. 295 (Truk).
Monarcha (Metabolus) rugensis Gray, Cat. Birds Trop. Is. Pacific Ocean, 1859, p. 19 (Caroline Islands).
Geographic range.—Micronesia: Caroline Islands—Truk.
Characters.—Adult male: White feathers (with dark bases) throughout except for black ones on forehead, lores, chin, and throat; chin and throat with steel-blue gloss; tips of second to fifth or seventh primaries black, black coloring extending along inner webs; shafts of primaries and basal half of tail feathers black; bill and feet black.
Adult female: Resembles adult male, but generally sooty-black, darker above; under tail-coverts and sometimes rump splotched with white; white coloring may also be present on tips of secondaries, on chin, and on tail.
Immature: Resembles adult, but bright cinnamon on upper parts and on wings and tail; inner webs of primaries grayish or dark brown, shafts of primaries lighter on basal half; lores, chin and throat white or washed with creamy-buff; breast and abdomen whitish, washed with cinnamon, sides darker rufous, under wing-coverts, axillaries, and under tail-coverts usually light rufous although somewhat variable in color; basal part of bill yellow, tip of bill horn colored. Immatures may be observed in all stages of color change toward the adult condition.
Measurements.—Measurements are listed in [table 40].