Cyana determinata (Walker, 1862)

(Pl. 1: 6; 3: 6)

Bizone determinata Walker, 1862, J. Proc. Linn. Soc. Zool. 6: 120. TL: Borneo (Sarawak).

Chionaema ridleyi Hampson, 1900, Cat. Lep. Phal. Br. Mus. 2: 300; Draudt, 1914, 10: 169. TL: Singapore. Chionaema determinata: Hampson, 1900, Cat. Lep. Phal. Br. Mus. 2: 323, pl. 27: 7.

Chionaema biana f. insularis Draudt, 1914, in Seitz, Gross-Schmett. Erde 10: 174, fig. 161. TL: Borneo, Java. Cyana biana [sic.] insularis: Roepke, 1946, Tijdschr. Ent. 87: 29.

Cyana determinata: Holloway, 2001, Moths of Borneo 7: 337, pl. 1: 35, 36; Černy & Pinratana, 2009, 6: 40, pl. 6: 80.

Diagnosis. Wingspan ♂ 28 mm. This species shows extreme sexual dimorphism. This species is similar to C. bianca, but can be distinguished by the following characteristics: small size (28 mm); in male genitalia, valvae more rectangular; saccular process tapered, with sharply curved, long apical spine, slightly longer than valvae; aedeagus short, stout, and vesica with two groups of longer spines, fields of short, irregular spines, and scobination. In C. bianca, larger size (36–37 mm); in male genitalia, valvae tapered; saccular process finger-shaped, with short apical spine, almost same length with valvae; aedeagus stout, and vesica with fields of small to large, irregular spines.

Material examined. 1♂, Cambodia, Seima (N12˚16′44″, E107˚03′56″), 12.XI.2011 (Y.S. Bae et al.), Gen. Slide No. INU-1237.

Distribution. Cambodia (Seima), Sundaland, peninsular Malaysia, Thailand.

Remarks. Only one male had been collected up to now. This species is newly recorded from Cambodia.