Lectotype ♂ (here designated), “Murree [Hills, Punjab] / 7500 ft/June 18 / Dutt Coll”, “Presented by / R.L.E.Ford. / B.M.1949–487.”, “Roeslerstammia metaplastica Meyrick / det.T.B.Flecher”, “♂” (Fig. 1A, B), in BMNH. B.M. Genitalia slide No. 29548.

Paralectotype ♀, same labels as lectotype except for “♀” (Fig. 1C, D) , in BMNH. B.M. Genitalia slide No. 29549.

Lectotype ♂of Roeslerstammia hemiadelpha Meyrick, 1922 (here designated), “Murree Hills / Punjab / 7500 ft / May 1920 / Dutt Coll”, “Presented by / R.L.E.Ford. / B.M.1949–487.”, “Roeslerstammia hemiadelpha Meyrick / det.T.B.Flecher”, “in Cop /C” “♂” (Fig. 1E, F) , in BMNH. B.M. Genitalia slide No. 29550.

Paralectotype ♀of Roeslerstammia hemiadelpha Meyrick, 1922, same labels as lectotype except for “♀” (Fig. 1G, H), in BMNH. B.M. Genitalia slide No. 29551.

Distinguished from the other species by the narrow triangular creamy-white tornal spot of the forewing. In the male genitalia, the uncus is rectangular, apically bilobed and broad; the valva has a short sacculus terminating in a blunt process; the phallus is short, sinuate, and tapered toward the apex. In the female genitalia, the ductus bursae is slender, nearly straight; the corpus bursae is long-ellipsoidal, with a strongly sclerotized sword-shaped signum.

Male (Fig. 1A, E).

Forewing length 5.3 mm. Wing expanse 11.3 mm.

Head vertex, including between antennae, with raised pale yellow hairs; frons smooth, ochreous with golden luster, laterally pale yellow along eyes. Eyes moderate, interocular index ca 0.8. Antenna filiform, ca 0.9× as long as forewing; scales in flagellar segments near the middle of the antenna somewhat raised; scape pale yellow on basal half and dark brown on distal half; flagellum dark brown on basal 2/3, white on distal third, densely ciliate with sensory hairs ventrally. Labial palpus slightly upcurved, relatively long ca 2.2 × as long as horizontal eye diameter, 3^rd segment as long as 2^nd, entirely smooth, 2^nd pale yellow, 3^rd pale yellow with dark brown laterally.

Thorax tegula pale yellow (scales partly removed); mesonotum dark brown with metallic luster. Fore- and midlegs pale yellow, tarsomeres brown distally; hindleg pale yellow. Forewing, lanceolate, dark brown with metallic blue or golden luster; a narrow indistinct oblique marking present at basal 2/3 near costa, a line along fold from base, terminating in a narrow triangular creamy-white tornal spot; fringe dark brown. Hindwing dark brown, darker near apex; fringe dark brown.

Abdomen pale brown with golden luster, terminally with pale yellow tufts.

Male genitalia (Fig. 2). Uncus rectangular, apically broad and bilobed. Tegumen broad, slightly shorter than uncus. Gnathos consisting of two slender arms united medially with a membranous part. Valva rectangular; sacculus short, about 1/3 length of valva, terminating in a blunt process; a small pad of long hair scales near the base ventrally. Vinculum broad ventromedially; saccus cylindrical, as long as dorsal part of tegumen. Phallus, short, sinuate, tapered toward apex, with indistinct minute spine-like cornuti.

Female (Fig. 1C, G).

Forewing length 5.5 mm. Wing expanse 12.1 mm.

Similar to male but differs as follows: scales in flagellar segments near the middle of the antenna not raised; flagellum without dense sensory hairs ventrally. Forewing with the oblique marking on costa broader, but indistinct in “R. hemiadelpha”.

Female genitalia (Fig. 3). Papillae anales broad and truncate in ventral view, nearly rectangular in lateral view. Apophysis posterioris slender, 0.7 × as long as papilla analis. Apophysis anterioris slender and moderate in length, 0.6 × as long as eighth tergite. Eighth tergite weakly sclerotized, dorsal posterior margin nearly straight. Ostium bursae situated at posterior margin of eighth abdominal segment, posterior margin weakly emarginate at middle. Ductus bursae slender, nearly straight. Ductus seminalis attached to ductus bursae near ostium. Corpus bursae long-ellipsoidal, with a strongly sclerotized sword-shaped signum.

Unknown.

India (Punjab).

Meyrick (1921) described R. metaplastica from the “Murree Hills, Punjab” based on five specimens collected by Dutt in June. Subsequently, Meyrick (1922) described R. hemiadelpha based on six specimens, which were collected by the same collector in the same locality in May 1920. Meyrick distinguished his two species on the basis of external characters such as coloration and wing markings (see Fig. 1). Since then, these specimens have not been studied again and they have been regarded as two distinct species following Meyrick. Both the male and female genitalia of some syntypes of R. metaplastica and R. hemiadelpha were examined, but there were no differences in the shape of male or female genitalia between the two taxa. Therefore, it was concluded that the latter is a junior synonym of the former. Of the original syntype series, only one male and female of each taxon was found in BMNH: both males are selected as lectotypes.

Holotype male, “Tianpingshan (1,500 m)/ Badagongshan/ Hunan, China/ 26–27.v.2009/ G.H. Huang & M. Li”, in HUNAU. Paratypes 3 males, same label as holotype, in HUNAU; 1 female, same label as holotype, in ELKU.

Distinguished from other Roeslerstammia species by the triangular white marking on the costa of the forewing. In the male genitalia, the uncus is triangular, apically narrow and bilobed; the valva has a blunt process on the median part of the costa; the phallus is long, its basal half straight, distal half strongly upcurved and sinuate. In the female genitalia, the ductus bursae is stout, the caudal part upcurved; the corpus bursae is ellipsoidal, with a thorn-shaped signum.

Male (Figs 4A, 5D).

Forewing length 7.3 mm in holotype, 6.7–7.1 mm in paratypes.

Wing expanse 15.3 mm in holotype, 13.5–14.3 mm in paratypes.

Head vertex, including between antennae, with raised blackish brown hairs anteriorly, yellow hairs posteriorly; frons smooth, ochreous with golden luster, laterally along eyes blackish brown with a metallic blue lustre (Fig. 5D). Eyes relatively large, interocular index ca 1.0. Antenna filiform, 0.8 >(apical part lost)× as long as forewing; scales in flagellar segments near the middle of antenna somewhat raised (Fig. 7B); scape blackish brown with metallic blue lustre; flagellum dark brown on basal 1/3, white on distal 2/3 (apical part lost). Labial palpus slightly upcurved, relatively long ca 2.3 × as long as horizontal eye diameter, 3^rd segment slightly longer than 2^nd; entirely smooth and terminally acute, pale yellow (Fig. 5D).

Thorax tegula dark brown with metallic blue luster; mesonotum dark brown with metallic blue or golden luster. Foreleg dark brown, partly mixed with pale yellow; midleg pale yellow with dark brown tibial spurs; hindleg pale browish gray dorsally, tibia with pale yellow hairs ventrally. Forewing lanceolate, apex narrowly rounded, dark brown with metallic blue or golden luster; a clear triangular creamy white marking present at basal 2/3 of costa; fringe dark brown; veins R4 and R5 stalked, R5 reaching to costa (Fig. 6). Hindwing dark brown, darker near apex; fringe dark brown. Hindwing with frenulum consisting of a long bristle.

Abdomen dorsal part pale brown with golden luster, terminally with pale yellow tufts of long hairs. Ventral part similar to dorsal part, terminally with creamy yellow smooth scales.

Male genitalia (Fig. 8). Uncus triangular, apically narrow and bilobed. Tegumen broad, as long as uncus. Gnathos consisting of two slender arms united medially with a circular plate. Valva broad basally and narrowed distally, with a blunt process on median part of costa; sacculus short, about 1/3 length of valva, terminating in an indistinct projection; a small pad of long hair scales near the base ventrally. Vinculum narrow ventrally; saccus cylindrical, as long as dorsal part of tegumen. Phallus long, basal half straight, distal half upcurved and sinuate, with a band of minute spine-like cornuti.

Female (Fig. 4B).

Forewing length 7.6 mm. Wing expanse 15.8 mm.

Similar to male but differs as follows: antenna filiform, 1.1× as long as forewing. Scales on antennal flagellar segments not raised; flagellum dark brown on basal half and apical 1/7, white on distal half to near apex. Hindwing with frenulum of two slender bristles.

Female genitalia (Fig. 9). Papillae anales narrow and apically pointed in ventral view, nearly triangular in lateral view. Apophysis posterioris slender, 0.7 × as long as papilla analis. Apophysis anterioris short and basally broad, 0.3 × as long as eighth tergite. Eighth tergite strongly sclerotized, dorsal posterior margin weakly emarginate at middle. Ostium bursae situated on anterior margin of eighth abdominal segment, posterior margin nearly straight. Ductus bursae stout, caudal part upcurved. Ductus seminalis attached to ductus bursae near ostium. Corpus bursae ellipsoidal, with a thorn-shaped signum.

The specific name, an adjective, is derived from the type locality.

Unknown. The larvae of Roeslerstammia are first leafminers and then become skeletonizers and mainly feed on plants of Betulaceae (Alnus, Betula) and Malvaceae (Tilia) (e.g., Kyrki 1983, Heppner 2005). Recently Hirowatari et al. (2012) recorded Facaceae (Fagus) as the hostplant. The type locality of R. tianpingshana is located in a deciduous forest where Fagus lucida Rehder & Wilson is the dominant tree species. Although we carried out a survey for immature stages of the new species, no information on the hostplant was obtained.

China (Hunan Province).

On 26–27 May 2009, a total of four males and one female of the new species were collected in a light trap at Tianpingshan (1,500 m), Badagongshan National Nature Reserve, Hunan Province, China. On 12–14 August 2014, we ran a light trap in the same locality, but did not obtain additional material. The adults of R. pronubella and R. erxlebella are known to fly in spring and summer (Agassiz 1996, Huemer and Segerer 2001, Hirowatari et al. 2012) but we could not confirm the voltinism of the new species.