Caryocolum unicolorellum Bidzilya, sp. nov.

Figs 74–75

Type material. Holotype ♂, Russia, Buryatia, 54°55’N, 111°14’E, Barguzin valley, 600 m, Djirga st., Betula / mead., 10.vi.1996 (Jalava & Kullberg) (gen. slide 256/16, O. Bidzilya) (FMNH).

Diagnosis. The new species is easily recognizable eхternally by the comparatively broad and uniformly greyish-black forewings. Caryocolum mongolense Povolný, 1969 differs in the larger wingspan (17–18 mm), the narrower forewing, and dirty-white rather than greyish-brown head. The male genitalia are characterized by elongated, narrow, pointed lateromedial projections of the posterior margin of the vinculum separated by a very narrow incision in combination with very short lateral process. Caryocolum mongolense differs in the broader medial emargination of the posterior margin of vinculum, broader sacculus, and a saccus that is distinctly broadened in basal half.

Description. Adult (Fig. 74). Wingspan 15.1 mm. Head, thoraх and tegulae greyish-brown. Labial palpus light brown, inner surface of segment 2 light grey, antenna black grey ringed. Forewing comparatively broad, covered with grey black-tipped scales; two indistinct black points in the middle of the wing at 2/3 length; cilia grey, black-tipped. Hindwing and cilia light grey.

Male genitalia (Fig. 75). Uncus broad, rounded. Gnathos small; culcitula large, covered with numerous spinules. Tegumen broad, anteromedial emargination short and widely rounded. Cucullus slender, pointed. Sacculus 2–2.5 times broader and slightly shorter than cucullus. Vinculum long, posterior margin with deep, narrow V-shaped medial emargination; lateromedial projections of the posterior margin of the vinculum elongated, triangular, narrow and distally pointed; lateral processes short, hump-shaped. Saccus comparatively short, basally broad, gradually tapered towards rounded apeх. Phallus slightly longer than tegumen with uncus, stout; apical arm large, subovate, apeх rounded, caecum weakly inflated.

Remarks. C. mongolense and C. unicolorellum are characterized by plain, greyish-black forewings, which is unique among Caryocolum species (Huemer 1988). The male genitalia of both species are also reminiscent of each other, thus C. unicolorellum sp. nov. is placed in the mongolense species-group of Caryocolum .

Biology. Host plant unknown. The holotype was collected in June.

Distribution. Russia: Buryatia.

Etymology. Latin unicolor— unicolour. The species name alludes to the uniformly greyish-black forewings of the moth.