Periacma ferialis Meyrick, 1894

Wang, Shuxia & Xu, Zhixin, 2024, Taxonomy of the genus Periacma Meyrick (Lepidoptera: Autostichidae) from China, with a checklist of the world species, Zootaxa 5399 (2), pp. 101-129 : 106-108

Periacma ferialis Meyrick, 1894

( Figs 4 , 21 , 35 )

Periacma ferialis Meyrick, 1894: 21 . TL: Burma. TD: BMNH.

Material examined. CHINA, Yunnan: 1♂ 7♀, Houshan, Jingdong , 1140 m, 5‒23.VI.2013, leg. ZG Zhang, slide Nos. LiSR16104♂, LiSR16105 ♀, XZX20850 ♀, XZX20866 ♀; 1♂, Qiunatong Village, Bingzhongluo Town , Gongshan County, Nujiang , 1767 m, 18.VI.2017, leg. KJ Teng et al., slide No. ZXJ18155

Diagnosis. This species can be distinguished from other known species of the genus by the semicircular gnathos with spinules, and the costal part of the valva with a triangular process ventrally.

Redescription. Adult ( Fig. 4 ). Wingspan 8.0 ‒ 12.0 mm.

Head. Vertex and frons yellow. Labial palpus yellowish white on dorsal surface, yellow mixed with brown scales on ventral surface, brown on outer side of basal segment. Antenna with scape yellow on ventral surface, black on dorsal surface except yellow terminally; flagellum yellow, alternated with black on dorsal surface.

Thorax. Mesonotum and tegula orange yellow. Forewing orange yellow; costal margin with brown band narrowed to basal 1/3; dorsum with wide, arched brown speckle from base, oblique outward to fold and along fold to before tornus above dorsum; discal spot brown, close to preceding speckle; postmedial fascia purplish brown, from costal 2/3 to tornus, slightly arched outward; apical fascia brown, sub-triangular; fringe yellow. Hindwing grey; fringe yellow. Legs yellow, except tarsomeres 3 4 of fore- and midlegs black; on ventral surface, foreleg black at base of coxa; on dorsal surface, foreleg with femur and tibia black, tarsus with scattered black scales at first tarsomere, midleg with femur black, tibia black at base and on distal half, tarsus black at middle of first tarsomere and at base of second tarsomere; on outer surface, hindleg with femur black at apex, tibia black at base, tarsus with black scales.

Male genitalia ( Fig. 21 ). Uncus wide at base, narrow from near base to middle, distal half oval-shaped, gradually widened from 1/2 length to before narrowly rounded apex. Gnathos with ventral plate being a large semicircle with dense short spines, finely combed along anterior margin. Valva with costal part narrow at base, widened to basal 2/5, then subparallel to subapex, narrowly rounded at apex, bearing a sclerotized triangular process at middle on ventral margin; costa slightly concave medially; dorso-proximal process slender, clubbed; sacculus broad, triangular, narrowed from wide base to pointed apex, reaching ventral spine of valva, ventral edge heavily sclerozed, forming a narrow band. Saccus short and broad, almost straight on anterior margin. Aedeagus 3/5 as long as costal part of valva, gradually widened to basal 3/4, then narrowed to before pointed apex, heavily sclerotized and strongly curved distally.

Female genitalia ( Fig. 35 ). Papilla anale bell shaped, densely setose. Apophysis anterioris 2/5 length of apophysis posterioris. Eighth sternal plate slightly sclerotized and spinulate posteriorly, lined with large setae on posterior margin. Lamella antevaginalis a wide plate, concave posteromedially. Antrum shorter and narrower than ductus bursae, sclerotized laterally. Ductus bursae membranous, short and wide. Corpus bursae membranous, ovoid; signum transversely elongate, being a rough-edged plate, medially widened and with a spine.

Distribution. China (Jiangsu, Taiwan, Yunnan, Zhejiang).

Note. Caradja & Meyrick (1935) reported the distribution of this species in Jiangsu, Taiwan and Zhejiang. The female of this species is described for the first time herein.

Figures

FIGURES 1‒9. Adults of Periacma spp. 1. P. acriuncata; 2. P. anterosinuata sp. nov., holotype; 3. P. falcata sp. nov., holotype; 4. P. ferialis; 5. P. himalayensis; 6. P. kunai; 7. P. largiloba sp. nov., holotype; 8. P. laterispinulosa sp. nov., holotype; 9. P. lianzhouensis, comb. nov. Scales = 2.0 mm.

FIGURES 19–24. Male genitalia of Periacma spp. 19. P. anterosinuata sp. nov., slide No. XZX20611, holotype; 20. P. falcata sp. nov., holotype, slide No. XZX20831; 21. P. ferialis, slide No. LiSR16106; 22. P. himalayensis, slide No. XZX767; 23. P. largiloba sp. nov., holotype, slide No. LiSR16109; 24. P. laterispinulosa sp. nov., holotype, slide No. XZX20576. Scales = 0.2 mm.

FIGURES 33‒38. Female genitalia of Periacma spp. 33. P. acriuncata, slide No. XZX20717; 34. P. anterosinuata sp. nov., paratype, slide No. XZX20612; 35. P. ferialis, slide No. XZX20850; 36. P. himalayensis, slide No. XZX20768; 37. P. kunai, slide No. XZX20814; 38. P. laterispinulosa sp. nov., paratype, slide No. ZXJ18472. Scales = 0.5 mm.