Zosterops semperi rotensis Snouckaert, Alauda. (2), 4, 1932, p. 459 (Rota); Yamashina, Tori, 7, 1932, p. 399 (Rota); Hand-list Japanese Birds, rev., 1932, p. 173 (Rota).
Zosterops conspicillata rotensis Hand-list Japanese Birds, 3d ed., 1942, p. 193 (Rota); Mayr, Amer. Mus. Novit., no. 1269, 1944, p. 7 (Rota); idem, Birds Southwest Pacific, 1945, p. 299 (Rota); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 73 (Rota).
Geographic range.—Micronesia: Mariana Islands—Rota.
Characters.—Adult: Upper parts and sides of neck between "warbler green" and "pyrite yellow" becoming lighter on the rump; auriculars light yellowish-green; orbital ring white; fronto-loral band narrowly tinged with yellow; underparts dingy yellow; wing and tail feathers dark with light greenish-yellow edges; upper mandible light brown; lower mandible light yellowish-brown; feet light brown.
Resembles Z. c. conspicillata, but brighter greenish-yellow above; chin and throat yellow like rest of underparts; fronto-loral band tinged with bright yellow; auriculars resemble closely the upper parts in color; narrow orbital ring.
Measurements.—Measurements are listed in [table 50].
Specimens examined.—Total number, 5 (3 males, 1 female, 1 unsexed), from Mariana Islands, USNM—Rota (Oct. 18, 20, 22).
Nesting.—Yamashina (1932a:399) records the taking of one nest containing two eggs at Rota on March 7, 1931.
Molt.—Specimens taken in October were in molt.