Promalactis polyptycha Wang, sp. nov.

(Figs 27, 60)

Type material. Thailand: Holotype ♂, Plateau 500 m N of HQ, Phu Khieo WS, Chaiyaphum, 900 m, 5–10.XI.1991, leg. I.J. Kitching & A.M. Cotton, slide No. NHMUK010317019.

Paratype. 1♂, same data as holotype .

Diagnosis. The new species can be distinguished from other known species of the group by the valva produced into a bird head-shaped process distally and the phallus with many pleats distally. It is similar to P. apicuncata Wang, 2018, but can be distinguished by the gnathos with a sub-digitate mesial plate, the costa concave beyond the middle, and the juxta without distinct lateral lobes. In P. apicuncata, the gnathos has a sub-trapezoidal mesial plate, the costa is concave before middle, and the juxta has elongate slender lateral lobes.

Description. Adult (Fig. 27). Forewing length 4.0– 4.5 mm.

Head. Vertex snowy white; frons brown; occiput ochreous brown, with tufted yellow scales laterally. Labial palpus with second segment rust brown on outer surface, orange yellow on inner surface; third segment black except white apically. Antennal scape white dorsally, greyish white ventrally; flagellum dark brown, alternating with white dorsally.

Thorax. Mesonotum and tegula ochreous brown. Forewing orange yellow; markings white edged with black scales: costal spot triangular, from distal 1/3 oblique outward to above posterior angle of cell, sinuate laterally; basal streak from dorsum to above base of fold; antemedian streak from middle of dorsum to basal 2/5 of anterior margin of cell, slightly curved outward, subparallel with basal streak; dorsal streak finely slender, from before end of fold oblique outward and reaching inner margin of tornal spot; tornal spot large, ovate, reaching below posterior angle of cell; apical spot ovate; termen with two small spots below costal spot, interrupted by black scales; fringe yellow. Hindwing and fringe grey. Foreleg black except femur greyish white dorsally, tibia with white spot at base and middle, with a tuft of white scales at apex, tarsus white at apices of basal two tarsomeres; midleg brown ventrally, black dorsally, tibia with a white spot at base, with a tuft of white scales at apex, tarsus white at apices of basal two and apical tarsomeres; hindleg yellowish brown ventrally, black dorsally, tarsus white at apices of basal four tarsomeres and on entire apical tarsomere.

Male genitalia (Fig. 60). Uncus wide at base, narrowed to distal 1/3, thereafter uniformly slender to apex, heavily sclerotized distally and laterally. Gnathos longer than uncus; mesial plate short, sub-digitate, rounded apically; basal arm widely band-like, longer than mesial plate. Tegumen furcate from near posterior margin; lateral arm triangular, narrowed to anterior end. Valva with basal 2/3 parallel sided, distal 1/3 slightly narrower, produced into a broad bird head-shaped process acute at apex and finely serrate on dorsal margin; costa concave beyond middle; sacculus slightly concave beyond middle dorsally, distal 2/5 setose, produced into a free process narrowed to pointed apex and curved dorsad. Saccus small, triangular, narrowed to rounded apex, shorter than uncus. Juxta shorter than uncus, U-shaped, produced anteriorly. Phallus as long as valva, with dense longitudinal pleats distally; cornutus spine-shaped, with tiny spines around its base.

Female unknown.

Distribution. Thailand.

Etymology. The specific epithet is derived from the Latin polyptychus, referring to the pleats of the phallus.