Wingspan: 20 mm. Head light brown. Labial palps composed of 3 segments: first segment short, light brown; second segment with a long bicoloured tuft of light and dark brown scales; third segment longest, bent upwards with the-distal part pointed. It is very light brown and the tip has pure white scales (Fig. 2). Maxillary palp short, light brown, apex pointed with some white scales. Antennae: scapus and pedicel light grey-brown; flagellomeres light brown, each with a white ring.

Forewing (Fig. 1) chocolate brown, with rusty lustre. Basal area tricoloured: dark brown near costal margin, light brown near dorsal margin, white scales in central part. Costal margin proximally dark brown, small dark spots visible at 1/3 of its length, central and distal part light brown. A longitudinal streak reaching from base to two thirds of the wing ending bowed upwards and with a small whitish triangular spot edged with black pointing towards the corner. The streak is dark brown to blackish. Central part, to termen margin, light brown. Termen margin darker. Cilia white-brown, with 2 thin interrupted darker lines. Hindwing light grey, with similarly coloured cilia and a darker dividing line.

Thorax dark brown. Abdomen light grey-brown with a longitudinal blackish streak in the middle.Legs are black ringed with narrow white rings.

Female genitalia (Figs 5-8): Papilla analis membranous, broad, with scanty hair-like spines. Posterior apophyses long and thin, hook-shaped. Anterior apophyses thin, noticeably narrowing, shorter than posterior apophyses. Ostium bursae oval, small, antrum triangular in outline, with gently rounded margins, strongly sclerotized, markedly constricted near ductus bursae. Ductus bursae short and wide, strongly sclerotized, immediately under antrum strengthened with longitudinal sclerites, which makes it more narrow. Remaining part of ductus bursa slightly narrower, only near inception of bursa copulatrix slightly dilated, emitting a short membranous ductus bulla, broadening into a small, membranous bulla seminalis. Ductus seminalis narrow, markedly sclerotized. Bursa copulatrix small and oval, strongly strengthened with spinules; signum absent.

Male unknown.

Biology: Only the collecting data are known.

Type locality: Zhe Gu Shan pass Barkam area in northern Sichuan Province on the eastern edge of the Tibetan Plateau, at an elevation of 3300 m. The type locality (Fig. 3) is a shrubby humid alpine meadow surrounded with mountainous Picea forest.

Remarks: Rhigognostisbarkamensis Baraniak & Larsen, sp. n. can easily be distinguished from other known species of this genus by morphological features. Scales on forewings coloured like in R. erysiphaea (BARANIAK et al., 2015) but the shape and colour of the narrow and dark longitudinal streak in R. barkamensis is in contrast to the white narrow pattern in R. erysiphaea.The external morphology of R. viatica (Durrant, 1906) was examined by first author during his visit to BNHM in London (Fig. 4). In the original description R. viatica is placed between R. senilella (Zetterstedt, 1839) and R. annulatella (Curtis, 1832) and thus the differences to barkamensis are large. The structure of the female genitalia especially antrum, is generally similar to that of R. incarnatella and R. schmaltzella (Zettersted, 1839) (BENGTSSON, 2011). The difference is pronounced with a constricted and sharp angle to ductus bursa. The opening of antrum is not circular but slightly constricted, like in R. annulatella. Ductus bursae wide but short, under antrum strengthened with two sclerites. Uniform sclerotization of its further part makes it different from other known species, where it is at least partly membranous. Bursa copulatrix of the new species is small, oval, strongly sclerotized, without signum. Its oval shape and strengthening of its walls by spinules also distinguishes it from other known species, where bursa copulatrix is spherical, membranous, usually with paired signa.

Etymology: The species is named after the collecting area.