Species of Diduga are small in size. The proboscis is fully developed, the labial palpus is slender, directed upwards over the top of the head; the male antennae vary from ciliated to bipectinated. The tibial spurs are long.

In the male abdomen, the 8^th tergite is narrowed, with long and slender apodemes (Fig. 13); and the genitalia has narrow but long lateral hairpencils in many species. The configuration of valva may vary; usually they are simple, long, slender, and tapered, or short with several distinct processes, sometimes showing bilateral asymmetry. In the female genitalia, the ductus and corpus bursae range considerably in length.

Most species have brown forewings with white or yellowish margins along the costa and distally, or forewings are medium brown with darker fasciae and stigmata. There are often various hairpencils and androconial tufts on the wings of males. In addition, the forewings have a complete set of veins arising from the cell, R₁ to R₃ all extending to the costal margin, R₄ and R₅ have a common stem, the others are independent. In the hindwing, R_S and M₁ have a common stem, M₂ is absent, the others are independent (Fang 2000; Holloway 2001).

Holotype: China: ♂; Chongqing, Jiangjin, Mt. Simian; 28.584°N, 106.356°E, elevation 1103 m; 12–13.VII.2018; leg. H.L. Han & C. Zhang; genit. prep. no. ztt-070-1; in NEFU. Paratypes: 3♀♀; same data as holotype; genit. prep. nos. ztt-073-2, ztt-074-2, ztt-080-2; in NEFU.

Figures 1–6. 

Adults of Diduga spp. 1 D. simianshana sp. nov., male, holotype, China (Chongqing) 2 dittos, female, paratype, China (Chongqing) 3 D. nigridentata, male (after Bayarsaikhan and Bae 2019) 4 D. quinquicornuta, male (after Bayarsaikhan and Bae 2019) 5 D. chebalinga sp. nov., male, holotype, China (Guangdong) 6 ditto, female, paratype, China (Guangdong). CB: costal band; IE: inner edge of costal band; TB: terminal band.

The new species is externally similar to D. nigridentata Bayarsaikhan & Bae, 2019 (Figs 3, 15). It can be separated from the latter by the following characters (D. nigridentata details are between parentheses): the ground color of the forewing is darker; an approximate right-angled bulge at tornal area (with arched bulge); the ground color of the hindwing is darker, in the male genitalia, the two basal projections of valva are longer than tegumen (shorter); the left cucullus bears two small spines (only a single long spine); the right cucullus and costal process are fused (separated); the cornutus is long and straight (short and arched).

Adult: (Figs 1, 2) Wingspan 13–14 mm. Head yellow; antenna filiform, brown. Thorax dark brown, patagium and tegula yellow. Abdomen with pale yellow anal tuft. Forewing with dark brown ground color; costal band broad, yellow, with several small, dark brown dots, its inner edge undulated; median line absents at costa but present as a dot at the inside inner edge of costal band; terminal band of same color as costal one, inner edge of terminal band undulated, with an approximate right-angled bulge at tornus; terminal line with an admixture of brown and yellow; fringe yellow. Hindwing smoky brown, with diffuse, small, dark brown flecks; fringe pale to smoky brown, light yellow basally. Male genitalia (Fig. 14). Tegumen triangular, weakly sclerotized, as long as uncus; the basal projections of tegumen asymmetrical, strongly sclerotized, clavate, with a triangular denticle distally; left one with large hemispherical tubercle distally, right one fist-sharped. Vinculum U-shaped, sclerotized, thick. Valva rather flat, broad, asymmetrical; the left one longer and wider; sacculus long, mostly straight, barely shorter than whole valva, saccular process curved, fingerlike, with long, sclerotized terminal spine; costa very narrow, thick, as long as valva; cucullus strongly sclerotized and tapered into elongate subtriangular process, with a long stout spine distally; the right one flat, sacculus narrow and straight, saccular process curved, fingerlike, with a shorter terminal spine; costa narrow; cucullus strongly sclerotized and tapered, with a long stout spines distally. Uncus sinuous, short and thick basally; swollen before pointed, hooked apex. Aedeagus cylindrical, smoothly curved, coecum swollen and short, ca 1/9 as long as overall aedeagus; vesica with a small triangular cornutus, and a slender, long cornutus accompanied by a small band of hair. Female genitalia (Fig. 22). Ostium bursae rough and weakly sclerotized, the 8^th abdominal segment shaping a deeply invaginated V-shaped ostium bursae; two triangular lobes at both sides. The posterior margin of the 7^th abdominal has a distinctly sunken fold. The 6^th abdominal segment slightly thickened posteriorly, with slight ridges on both sides. Ductus bursae long and narrow, twisted at middle, its posterior half strongly sclerotized, flat and straight, and anterior one membranous, partly rugose. Corpus bursae globular, membranous, with a ring-shaped signum band. Apophysis anterior rather thick, ca 5/8 as long as apophysis posterior, this slender and long. Papillae anales cone-shaped, covered with setae.

The species is named after the type locality, Mt. Simian, Chongqing Municipality, China.

China (Chongqing: Mt. Simian) (Fig. 28).

The species was collected by light trap close to an evergreen broadleaf forest. The main tree species in the collecting biotope are Engelhardia roxburghiana Wall.,1831 and Cunninghamia lanceolata (Lambert) Hooker, 1827.

Holotype: China: ♂, Prov. Guangdong, Shaoguan, Chebaling National Nature Reserve; 24.731°N, 114.267°E, elevation 463 m; 29.IV–3.V.2019; leg. H. L. Han & J. Wu; genit. prep. no. ztt-078-1; in NEFU. Paratype: 1♀; same data as holotype; genit. prep. no. ztt-077-2; in NEFU.

The new species is externally similar to D. quinquicornuta Bayarsaikhan & Bae, 2019 (Figs 4, 17, 24). It can be separated from the latter by the following characters (D. quinquicornuta details between parentheses): the wingspan is broader; the tegumen is thin (thick); the right costal process is long, wide, flat, and rounded distally (short, hornlike, sharp distally); the cucullus is sclerotized, thick, spoon-shaped, with a short horn distally (poorly sclerotized, club-shaped, wrinkled); the uncus is slightly swollen medially, not bending ventrally (wider and flat, hooked apex); in the female genitalia, the ostium bursae is strongly sclerotized, wrinkled, and bending to the left (weakly wrinkled, typical); the ductus bursae is curved, gradually broadening from anterior to posterior (typical, tapered); the corpus is divided into two parts, a posterior part membranous, and the anterior one globular, densely covered small flecks (long oval, anterior half with dense, small flecks, and more than 6 signa forming a vertical semicircle, posterior half membranous, smooth).

Adult: (Figs 5, 6) Wingspan 13–14 mm, female larger than male. Head yellow; antenna filiform. Thorax dark brown; patagium, and tegula yellow. Abdomen brown, with pale yellow anal tuft. Forewing with dark brown ground color; costal band broad, yellow, with dispersed small, dark brown scales; its inner edge undulated; terminal band of same color as costal one, and its inner edge undulated, with an approximately right-angled bend near tornus; terminal line with an admixture of brown and yellow; fringe yellow. Hindwing smoky brown, fringe pale to smoky brown. Male genitalia (Fig. 16). Tegumen triangular, thin, and narrow superiorly. Vinculum broadly V-shaped, sclerotized, thick. Valva asymmetrical and bifurcated; in the left one, basal projections of valva bifurcated, one short, the other one ca 6 times as long as the short one; sacculus thick, gradually broadening distally; saccular process narrow, smoothly arched; costa rather broad, smooth, with a curved, cone-shaped ampulla; costal process strongly sclerotized, thick, wedge-shaped; harpe short, cone-shaped, strongly sclerotized, cucullus spoon-shaped, with short, sclerotized horns distally; in the right one, sacculus weakly sclerotized, swollen, basal process lumpy; saccular process strongly sclerotized, short, sharp distally; costa broad, smooth, with a long, flat ampulla; costal process membranose; cucullus strongly sclerotized, bifurcated, one slender, rounded distally, the other one finger-shaped, distally. Uncus thick, covered with setae, slightly swollen medially, ca 7/9 as long as tegumen. Aedeagus weakly sclerotized, with small bulge at coecum; vesica with a small flecks plate at ventral part of basal. Female genitalia (Fig. 23). Ostium bursae broad, bent to left, with thick and sclerotized frame; lamella antevaginalis tongue-shaped. The 7^th abdomere strongly sclerotized, wrinkled, densely covered with setae. Ductus bursae curved, gradually broadening posteriorly. Corpus bursae divided, anterior half globular, densely covered with small flecks, posterior half membranous, thin, and wrinkled. Papillae anales broad, covered with setae.

The species is named after the type locality, Chebaling National Nature Reserve, Guangdong Province, China.

China (Guangdong: Chebaling) (Fig. 28).

The species was collected using a light trap close to a typical evergreen broadleaf forest of the mid-subtropics near the Zhangdong River. The main tree species in the collecting biotope is Cunninghamia lanceolata (Lambert) Hooker, 1827.

Holotype: Malaysia: ♂, Sabah, Borneo Jungle Girl Camp; 5.442°N, 116.451°E, elevation 1223 m; 15–20.II.2019; leg. H. L. Han; genit. prep. no. ztt-110-1; in NEFU. Paratypes: 1♂, 2♀♀; same data as holotype; genit. prep. nos. ztt-100-1, ztt-102-2, ztt-040-2; in NEFU.

Figures 7–12. 

Adults of Diduga spp. 7 D. chewi sp. nov., male, holotype, Malaysia (Borneo) 8 ditto, female, paratype, Malaysia (Borneo) 9 D. trichophora, male (after Bucsek 2012) 10 D. kohkongensis, male (after Bayarsaikhan & Bae, 2018) 11 D. hollowayi sp. nov., male, holotype, Malaysia (Borneo) 12 ditto, female, paratype, Malaysia (Borneo).

Figure 13. 

Abdomen of male adult of the genus Diduga.

The wing pattern of the new species is similar to that of D. trichophora Hampson, 1900 (Figs 9, 19). It can be separated from the latter by the following characters (D. trichophora details are between parentheses): the forewing is broader (narrow); the male hindwing is dark grey, broad fan-shaped (pale, narrow fan-shaped); in the male genitalia, the valva termination bifurcated distally (finger-shaped, sharp distally); the coecum is typical (bifurcated); the vesica has long, narrow band of flecks (without).

Figures 14–17. 

Male genitalia of Diduga spp. 14 D. simianshana sp. nov., holotype, genit. prep. No. ztt-070-1 15 D. nigridentata, 2019 (after Bayarsaikhan and Bae 2019) 16 D. chebalinga sp. nov., holotype, genit. prep. No. ztt-078-1 17 D. quinquicornuta (after Bayarsaikhan and Bae 2019). Scale bars: 0.5 mm.

Adult (Figs 7, 8). Wingspan 15.5–16.5 mm. Head yellow; antenna filiform. Thorax dark brown; patagium, and tegula yellow. Abdomen dark to brown, the latter with pale yellow anal tuft. Forewing with dark brown ground color; veins and inner margin more black; costa slightly angled at 1/4 of the wing; costal band broad, yellow, with several dots and patches; its inner edge undulated; terminal band of same color as costal one, with internally facing concavity at tornus, the inner edge of terminal band undulated; terminal line and fringe yellow; ventral side of inner margin with long, brown hair tuft. Hindwing dark grey to smoky brown; costa with longer scales in male; tornus area sunken; fringe brown. Male genitalia (Fig. 18). Tegumen triangular, weakly sclerotized, slightly longer than uncus. Vinculum U-shaped, sclerotized. Juxta large, linguliform, weakly sclerotized, inverted harpoon-shaped. Valva approximately diamond-shaped, rather flat and symmetrical; sacculus narrow, thick and straight, 2/3 as long as valva, this terminated by long straight, sharply pointed process slightly bifurcated before apex. Uncus hooked and slender, sharp distally. Aedeagus curved, short, thick; caecum slightly swollen, ca 1/4 as long as whole aedeagus; vesica with a long cornutus and a scobinate band medially. Female genitalia (Fig. 25). Ostium bursae infundibuliform, weakly sclerotized. Ductus bursae narrow, flat, moderately sclerotized, sinuous anteriorly. Corpus bursae globular, membranous, with a ring-shaped signum band covered by small spines and flecks. Base of apophysis anterior is a long, inverted triangle; apophysis posterior slender, long, slightly longer than apophysis anterior; Papillae anales cylindrical, weakly sclerotized, covered with setae.

Figures 18–21. 

Male genitalia of Diduga spp. 18 D. chewi sp. nov., holotype, genit. prep. No. ztt-110-1 19 D. trichophora (after Bucsek 2012) 20 D. hollowayi sp. nov., holotype, genit. prep. No. ztt-033-1 21 D. kohkongensis (after Bayarsaikhan & Bae, 2018). Scale bars: 0.5 mm.

The name “chewi” refers to Mr J. Chew, who is a person in charge in the camp site where the species was collected.

Malaysia (Borneo: Sabah) (Fig. 28).

The species was collected in a tropical rain forest area. Podocarpaceae and Myrtaceae are richest families in the collecting biotope, and mosses such as Himantocladium plumula (Nees) Fleisch., 1908, Hypopterygium tamarisci Bridel ex C.Müller, 1850, Fissidens wichurae Broth. & Fleisch., 1899 are also abundant.

Holotype: Malaysia: ♂, Sabah, Borneo Jungle Girl Camp; 5.442°N, 116.451°E, elevation 1123 m; 15–20.II.2019; leg. H. L. Han; genit. prep. no. ztt-033-1; in NEFU. Paratypes: 1♂; same locality as holotype; 24.IV–2.V.2016; leg. H. L. Han; genit. prep. no. ztt-085-1; 7♀♀; same data as holotype; leg. H. L. Han; genit. prep. nos. ztt-034-2, ztt-083-2, ztt-096-2, ztt-097-2, ztt-099-2, ztt-103-2, ztt-104-2; in NEFU.

The new species is similar to D. kohkongensis Bayarsaikhan & Bae, 2018 (Figs 10, 21, 27) but it can be separated from the latter by the following characters (D. kohkongensis details are between parentheses): the ground color of forewing is darker; the male antenna is bipectinate (ciliate); the inner edge of costal band approximately straight (undulate); the terminal line distinct, formed by brown dots (yellow); the ground color of the hindwing dark brown (grey); in the male genitalia, the editum is a small band, slightly bulging (formed by stout spines); the valva is narrow and asymmetrical (symmetrical, stout); the apical process of valva is slender, long spine-shaped, incurved inward terminally (strongly horn-shaped, weakly arched); the uncus is slender and hooked (with angular bulge ventrally); the vesica has two cornuti, one small, claw-shaped, the other long, slender, smoothly arched (a row of six irregular cornuti); in the female genitalia, the ductus bursae is narrower; the corpus bursae is approximately triangular, with a triangular signum band posteriorly (rectangular, membranous, with plate of small spines at anterior half).

Figures 22–27. 

Female genitalia of Diduga spp. 22 D. simianshana sp. nov., paratype, genit. prep. No. ztt-073-2 23 D. chebalinga sp. nov., paratype, genit. prep. No. ztt-077-2 24 D. quinquicornuta (after Bayarsaikhan and Bae 2019) 25 D. chewi sp. nov., paratype, genit. prep. No. ztt-102-2 26 D. hollowayi sp. nov., paratype, genit. prep. No. ztt-083-2 27 D. kohkongensis (after Bayarsaikhan & Bae, 2018). Scale bars: 0.5 mm.

Adult (Figs 11, 12). Wingspan 12–13 mm, female larger than male. Head yellow; male antenna bipectinate, female antenna filiform. Thorax brown; patagium and tegula yellow, the color of female lighter. Abdomen with pale yellow anal tuft. Forewing with dark brown ground color; costal band broad, yellow to canary yellow, its inner edge nearly straight; the inner edge of terminal band undulated, with a slight right angle at tornus; terminal line conspicuous, formed by brown dots; fringe yellow. Hindwing brown, costal band light brown; fringe brown to smoky brown. Male genitalia (Fig. 20). Tegumen triangular, weakly sclerotized, as long as uncus. Vinculum narrow, weakly sclerotized, very broadly U-shaped, with slightly produced semicircular saccus. Juxta flat, moderately sclerotized. Valva band-shaped, weakly sclerotized, covered with setae, asymmetrical; left valva with broad and moderately sclerotized sacculus, 3/4 as long as overall valva, saccular process in shape of a long spine bent internally at ca 90°; right valva as long as left one, its saccular process like left one albeit evenly hooked internally; costa very narrow, as long as valva. Uncus slender, slightly hooked. Aedeagus membranous, cylindrical; coecum short, 1/5 as long as overall aedeagus; vesica with a small claw-shaped cornutus, and long, slender, smoothly arched cornutus subterminally. Female genitalia (Fig. 26). Ostium bursae flat and membranous. Ductus bursae flat, weakly sclerotized. Corpus bursae membranous, with a triangular signum band posteriorly; right part strongly sclerotized, with a signum plate covered long spines, terminally connected to ductus bursae. Apophysis anterior short, apophysis posterior ca 2 times as long as apophysis posterior. Papillae anales cylindrical, weakly sclerotized, covered with setae.

The species is named after Dr J.D. Holloway, who conducted outstanding lepidopterological research in Borneo.

Malaysia (Borneo: Sabah) (Fig. 28).

Figure 28. 

Collecting sites of Diduga spp. Key: D. simianshana sp. nov.: China, Chongqing, Mt Simian (blue dot); D. chebalinga sp. nov.: China, Prov. Guangdong, Shaoguan, Chebaling (red dot); D. chewi sp. nov. and D. hollowayi sp. nov.: Malaysia, Borneo (both green dot).

The species was collected in a tropical rain forest area. Podocarpaceae and Myrtaceae are richest families in the collecting biotope, and mosses of Himantocladium plumula (Nees) Fleisch., 1908, Hypopterygium tamarisci Bridel ex C.Müller, 1850, Fissidens wichurae Broth. & Fleisch., 1899 are also abundant.