Diduga hanoiensis Bayarsaikhan & Bae, n. sp.

(Figs 4, 10, 16)

Type materials. Holotype: 1 ♂, Vietnam, Prov. Hanoi, BaVi N.P., 19.VII˗5.VIII.2010 (500 m), (Y.S. Bae & X.V. Le), Gen. Slide No. INU˗10012V. Paratypes. (2 ♀) Vietnam: 2 ♀, Prov. Hanoi, BaVi N.P., 19.VII˗5.VIII.2010 (500 m), (Y.S. Bae & X.V. Le), Gen. Slide No. INU˗10011V; 10015V.

Diagnosis. The wing pattern of this species is hardly distinguishable from many others of the genus Diduga. However, in male genitalia, apex of left valva with three, large strongly sclerotized, dentate margin, irregular apical processes, and apex of right valva with one large, waved, spine˗shaped process separates; in female genitalia, strongly sclerotized ostial plate with diverse sized spines in margin, and narrow, tube˗shaped ductus bursae weakly sclerotized whole of length, with short spines in irregular, elliptical plate in cervix of bursae this species well from all the other known Diduga species.

Description. Adult (Figs 4a, 4b). Length of forewing 5 mm in both sexes. Head, patagium and tegula deep yellow. Thorax dark brown. Forewing ground color dark brown, with broad, deep yellow costal margin, which hind border broadly waved; with row of small, dark brown dots or patches from basal of costa to tornus; cilia deep yellow. Hindwing ground color light brown; cilia light brown. Abdomen brown dorsally and deep yellow ventrally, with deep yellow anal tuft in male. Male genitalia (Fig 10). Uncus stout, club˗shaped, apex angular, heavily covered with setae. Tegumen irregularly triangular, weakly sclerotized. Valva asymmetric: in left valva, narrower than right valva, with strongly sclerotized, dentate margin, irregular processes in subapical area, and costal margin of valva with three large sclerotized, strongly angled, triangular process in basal area; apex of cucculus rounded, membranous; in right valva, stout, truncate, with broadly waved apex, with one large waved, finger˗shaped lower angle’s process (almost same length with uncus); apex of cucculus rounded, membranous, weakly covered with setae, almost same length with lower angle’s process. Juxta arch˗shaped. Saccus broadly “U”˗shaped. Aedeagus stout, waved, with weakly sclerotized apically and vesica with scobination. Female genitalia (Fig 16). Papillae anales weakly covered with setae. Ostial plate strongly sclerotized, with diverse sized spines in margin. Ductus bursae narrow, tube˗shaped, slightly waved, weakly sclerotized whole of length, with short spines in irregular, elliptical plate in cervix of bursae. Corpus bursae ovoid, membranous, without signum.

Distribution. Vietnam (Hanoi Prov.).

Etymology. The species is named for the type locality, Hanoi, Vietnam.