Review of the genus Ressia Sinev, 1988 (Lepidoptera: Cosmopterigidae), with descriptions of four new species from China Author Zhang, Di College of Life Sciences, Nankai University, Tianjin 300071, China Author Li, Houhun College of Life Sciences, Nankai University, Tianjin 300071, China & College of Life and Geographic Sciences, Kashi University, Kashi 844000, China; Xinjiang Key Laboratory of Biological Resources and Ecology of Pamirs Plateau, Kashi 844000, China text Zootaxa 2023 2023-10-30 5360 4 583 592 https://www.mapress.com/zt/article/download/zootaxa.5360.4.7/52135 journal article 10.11646/zootaxa.5360.4.7 1175-5326 10152774 E967718F-F071-49BC-B69D-D4D0E8979530 Ressia semilunata Li , sp. nov. ( Figs 7 , 13 , 18 ) urn:lsid:zoobank.org:act: 5A37CDAF-6DCB-46F9-9EA8-3FB1D4523D5F Type material. Holotype ♁. CHINA , Hainan : Tianchi , Jianfengling ( 18.73°N , 108.86°E ), 787 m , 15.I.2016 , leg. QY Wang et al. , slide No. ZD 21571. Paratypes : 1♁, Shuiman Town , Wuzhishan City , 650 m , 15.V.2007 , leg. ZW Zhang & WC Li , slide No. ZZW08027; 1♁ 1♀ , Wuzhishan , 738 m , 2.XI.2016 , leg. X Bai et al. , slide Nos. ZD 21562♁, ZD21582 ♀ . Diagnosis. The new species can be distinguished from its congeners by the forewings with markings encircled by black scales and the white subbasal fascia with anterior 1/4 much narrower and ill-defined; in the male genitalia by having a semilunate cucullus; and in the female genitalia by having a short tubular sterigma. Description. Adult ( Fig. 7 ). Wingspan 11.0–12.0 mm. Head . Vertex dark brown, frons grayish yellow. Antenna with scape pale yellow dorsally, dark brown ventrally, ringed with white terminally; flagellum with basal 2/3 dark brown and pale yellow dorsally, pale yellow ventrally, distal 1/3 pale yellow. Labial palpus with second palpomere pale yellow, dark brown at apex; third palpomere dark brown, pale yellow dorsobasally. Thorax . Dorsum of mesothorax and tegula dark brown. Forewing dark brown; markings white encircled by black scales: subbasal fascia from basal 1/4 of costal margin to dorsum, its anterior 1/4 much narrower and ill-defined, smaller spot at 1/2 and larger spot at 5/6 of costal margin respectively, subtriangular spot at end of fold; fringe concolourous to forewing. Hindwing and fringe dark brown. Legs with coxae and femora yellowish white, tibiae and tarsi dark brown, except tibiae yellowish white at basal 1/6, 1/2 and apex; first tarsomere ringed with yellowish white at base and apex, 4–5 tarsomeres yellowish white. Male abdomen and genitalia ( Fig. 13 ): Abdomen. Furcate process of eighth tergum with outer margin produced outward medially, with pointed apex. Pleural lobes of eighth segment oval, with a furcella at base on dorsal margin. Male genitalia . Socus with left brachium spatulate, about 1/4 length of right brachium; right brachium with basal 1/4 wide, uniformly slender medially, sharply narrowed from distal 1/4 to pointed apex, curved at distal 1/6, hooked apically. Valva with stalk aequilate; cucullus semilunate, with dense setae on ventral surface. Left valvella slender, curved at middle, slightly inflated distally, with dense setae ventrodistally. Phallus with basal 2/3 tubular, distal 1/3 tapered to narrowly rounded apex. Female genitalia ( Fig. 18 ). Apophyses posteriores 1.5 times as long as apophyses anteriores. Sterigma tubular, with a sclerotized ventral sac. Antrum relatively short, concave at middle on posterior margin. Ductus bursae membranous, twice length of apophyses posteriores. Corpus bursae pyriform, shorter than ductus bursae; signa being five small subcircular plates with small erect lamellar processes. Distribution. China ( Hainan ). Etymology. The specific epithet is derived from the Latin semi- and lunatus , referring to the shape of the cucullus.