Irepacma isomora (Meyrick, 1910), comb. nov.

(Figs 20, 21)

Periacma isomora Meyrick, 1910: 160 . TL: India. TD: NHMUK (Holotype examined).

Material examined. Tibet: 2♁, Zhangmu Town (27.98°N 85.97°E), Nielamu County, 1961 m, 8.VII.2019, leg. MJ Qi & JQ Deng, slide Nos. TZL19618, TZL19617 .

Diagnosis. Irepacma isomora can be distinguished by the sacculus with the symmetrical dorso-apical processes uniformly slender, and the asymmetrical ventro-apical processes with spines.

Redescription. Adult (Fig. 20). Wingspan 18.0‒ 18.5 mm.

Head yellow. Labial palpus yellow; first palpomere black, second one with black scales on outer surface. Antenna yellow on ventral surface; on dorsal surface, scape black, flagellum black basally and ringed with black distally.

Thorax. Mesonotum and tegula grayish black except yellow apically. Forewing yellow, with pale yellowish brown gray scales; costal margin with grayish brown scales at base; discocellular stigma rounded, black; discal and plical stigmata indistinct; fringe yellow. Hindwing yellowish brown; fringe yellow, mixed with gray. Legs yellow, with exceptions on ventral surface: femur and tibia of foreleg black, femur of midleg with black scales, tibia grayish black, tarsi of fore- and midlegs black at middle of first tarsomere and at base of other tarsomeres; on outer surface: tibia of hindleg grayish black, tarsus black at base of second and third tarsomeres.

Male genitalia (Fig. 21). Uncus subconical, obtusely rounded at apex. Gnathos reduced. Tegumen V-shaped, narrowed medially; lateral arm banded, slightly widened before apex. Valva with basal half slightly narrower than distal half, distal half subparallelly sided to obtuse apex, extending obliquely dorsad, setose ventrally; costa banded, reaching near dorso-apex of valva. Sacculus subquadrate, with two apical processes: dorsal apical process symmetrical, uniformly slender, curved; ventro-apical process shorter, asymmetrical: left process larger, with densely clustered spines, right process much shorter, with fewer short spines. Saccus triangular. Juxta subrounded, arched outward mediolaterally, incised from middle of posterior margin. Aedeagus slightly longer than 2/3 length of valva, basal 1/3 slender, gradually widened from basal 1/3 to basal 3/4, distal 1/4 rod-shaped, widened apically.

Distribution. China (Tibet); India.

Remarks. Irepacma isomora is transferred from the genus Periacma on a basis of a broad forewing without a fascia and a reduced gnathos in the male genitalia.