Male most similar to omelkoi, but separated by black frontal tuft and paler androconial scales. Female (if chrysopterella indeed is the female) difficult to separate from other unicolorous species, but usually frontal tuft darker. Female genitalia characterized by ductus spermathecae with 15 convolutions.
Description. Male. Forewing length 2.3-2.7 mm (2.47 ± 0.17, n=4), wingspan 5.2-6.1 mm. Head: frontal tuft black, palpi contrasting white; collar dark fuscous; scape yellowish white cream, posteriorly edged with brown, flagellum brown. Antennae with 25-29 segments (n=4).
Forewings and thorax shining fuscous, underside pale brown. Hindwings grey, covered with cream androconial scales, extending about into about 1/3 of fringe, along costal edge white and brown spatulate androconial scales as long as hindwing width. Abdomen with anal tufts, colour not noted.
Female. Unknown. Male genitalia. Capsule length 290 µm (n=2). Vinculum anteriorly bilobed. Uncus with widely separated short horns, these with lesser sclerotized 'windows' in middle. Gnathos with widely separated posterior processes. Valva length 190-200 µm (n=2), with pointed distal process of about 1/3 valval length, inner margin with prominent pointed lobe. Aedeagus 505-540 µm long (n=2), 200 µm wide at basis; slightly asymmetric; vesica with long cornuti arranged in two rows, pointing towards each other, in total about 65 long cornuti, distally 5 large triangular cornuti and basally smaller pointed and pectinate cornuti.
Hostplants. Quercus acutissima, Q. variabilis, two common deciduous oaks, widespread in degraded forest areas. Possibly also on Castanea crenata (see remarks in original publication).
Leafmines. Egg on leaf-upperside (n=6), or underside (n=1), usually on or against a vein. Mine a sinuous gallery throughout, first with narrow brown linear frass, filling 1/3 of mine, sometimes filling it completely; in final instar frass broadly dispersed, or coiled, black; occasionally narrower.
Larva. Yellowish white with pale brown head and narrow black tergites on metathorax and abdominal segments 1-8.
Japan: Tsushima, possibly Kyushu (chrysopterella), North Korea, China: Yunnan. Probably widespread in sino-japanese zone.
Life history. Insufficiently known, larvae found in October, adults reared from February-May, one adult collected in July (Korea). Probably at least bivoltine.
This taxonomic description is based on Van Nieukerken (2000).