Type. Lectotype of Cerostoma falculella (here designated): ♂, [Russia], “Irkutsk VII [18]66”; “coll. Erschov”, gen. slide Yps.–29 MP; red rectangular label “Lectotype Cerostoma falculella Erschoff, 1877” (ZINRAS).

Russia. 1♂, Peterburg [St.–Petersburg] suburb, 21 April [19]06, N. Kuznetcov leg., gen. slide Yps.–39 MP; 1♀, Pskov, 5 October 1907, Chistovsky leg.; 2♀, Irkutsk, coll. Grand Prince N.M. [Romanoff], gen. slide Yps.–32 MP, Yps.–33 MP (ZINRAS); 1♀, Chitinskaya obl., Nizhnii Chasuchei, 2 June 1995, V. Dubatolov, R. Dudko leg., gen. slide Yps.–34; 1♂, Jewish Autonomous Region, Radde, 17 July 2005, M. Ponomarenko leg.; Primorskii krai: 1♀, Sinegorka Mt. foot, 2 August 1999, M. Ponomarenko leg.; 1♂, Ussuriyskii reserve, 10 May 1995, Chistyakov leg.; 2♂, 3♀, 20 km SE Ussuriysk, Gornotaezhnoe, 20 August, 2 October 1994, 28, 29 April 1995, M. Ponomarenko leg., gen. slide Yps.–35 (♂) MP; 2♀, Vladivostok, Botanic garden, 17 April 1996, E. Beljaev leg.; 1♂, Shkotovskii distr., Litovka Mt., 22–25 October 1998; 1♂, Anisimovka, 9 October 1999, gen. slide Yps.–36 MP; 1♂, Chuguevskii distr., 16 km SE Yasnoe, Ussuri riv., “Pobedinskaya Polyana” hole, 2 August 2012, M. Ponomarenko leg.; 1♂, Sakhalin, Yuzhno–Sakhalinsk, 28 August 2010, V. Dubinina leg., gen. slide Yps.–37 MP (IBSS). Belorussia. 1♂, Vitebsk, 3 September 1975, V.I. Piskunov leg., gen. slide Yps.–38 MP (ZINRAS). Ukraine. 1♂, 1♀, Sumskaya obl., Lebedin, 10, 13 August 1968, V.I. Piskunov leg., gen. slide Yps.–30 (♂) MP, Yps.–31(♀) MP (ZINRAS).

Europe, Asia Minor, Middle East, Russia (European part, South Ural, Irkutskaya oblast’, Transbaikalia, Amurskaya oblast’, Primorskii krai), Korea and China (Beijing).

Our examination of the lectotype of Cerostoma falculella and specimens of Ypsolopha asperella from Europe, South Siberia and Russian Far East did not show sufficient differences to justify treating them as separate species. It should be noted that in the genitalia of the lectotype of falculella (Fig. 7) the ventral margin of the valva is slightly angled as it is in Far Eastern specimens of Ypsolopha asperella. Other characters (external and genitalic) can be more or less variable. No specific external and genitalic characters correlated with a particular generation were found nor any characters typical of European or Asian populations. Every generation whether of European or Asian populations contains specimens expressing the full spectrum of character variability. The life cycle of this species is studied insufficiently and it is difficult to ascertain how many generations there are. According to the examined material and published data the adults fly in the spring from March-May (Zagulyaev 1981; Gershenson 1997). Usually spring specimens appear worn with indistinct forewing pattern, suggesting that specimens flying in October overwinter and reappear in early spring. In summer the adults appear in July. Moths flying in spring and summer vary in wing span from 16 mm to 22 mm. The aedeagus in every studied specimen has two more or less recessed apical lobes, 1–3 large square apical denticles and 3–14 small preapical ones (Figs 8a-f). The lectotype of Cerostoma falculella, collected in July, has an aedeagus with two large square apical denticles (Fig. 8a), the same number as found in specimens of Ypsolopha asperella from Vitebsk (Belorussia) (Fig. 8e) collected in September and Anisimovka (Russian Far East) (Fig. 8f) collected in October. Specimens of Ypsolopha asperella from Sankt-Petersburg (Russia, European part) (Fig. 8c) and Gornotaezhnoe (Russian Far East) (Fig. 8b), both collected in April, have a single square apical denticle on the aedeagus whilst in specimens from Sumskaya obl. (Ukraine) collected in August the aedeagus bears three large square apical denticles. Thus, the number of apical denticles on the aedeagus is not correlated with spring and summer generations nor with the geographic distribution, and it is here interpreted as intraspecific variation. Other structures of the male and female genitalia in specimens from different populations are more or less uniform and do not demonstrate distinct differences. Therefore falculella Erschoff is considered to be a junior subjective synonym of asperella Linnaeus.

Type. Paralectotype of Cerostoma costibasella: ♀, [China], “Mien–Shan (prov. Shansi), Obere Höhe ca. 2000 m 9.7.1937. H. Höne”, “allolectotype of Cerostoma costibasella Car.” (designated by A. Popescu–Gorj) (MGAB).

Russia. Primorskii krai: 1♂, 20 km SE Ussuriysk, Gornotaezhnoe, 43°41'42"N, 132°09'24"E, 21 July 1994, gen. slide Yps.–40 MP; 3♂, 2♀, Chuguevskii distr., 39 km E Yasnoe, Snezhnaya Mt., altitude 1230 m, 43°42'56"N, 134°26'15"E, 31 July–1 August 2012, M. Ponomarenko leg. (IBSS).

China (Beijing, Hebei, Shanxi), Russia (Far East, first record).

The lectotype of Cerostoma costibasella Caradja, which was designated, together with an allolectotype, by Popescu-Gorj (1992), has not been found in MGAB, Bucharest. According to its label the ‘allolectotype’ was collected in the same locality as the lectotype but two days earlier. Certainly the allolectotype is conspecific with the lectotype as indicated by the unique wide lemon yellow costal fascia in the basal half of the forewing. This character was mentioned in the original description by A. Caradja (1939): “ ... ein breiter zitronengelber Kostalstreifen von Basis bis 1/2 ...”. Recently the type of Ypsolopha ulingensis Yang was studied and illustrated by Sohn (2011) and found to be identical in wing pattern with Ypsolopha costibasella, which was described from the neighbouring province of Shanxi and also from the mountains. An additional series of specimens of both sexes was collected in the Russian Far East on Mt. Snezhnaya. Their wing pattern is identical with that in Ypsolopha costibasella and Ypsolopha ulingensis, and their male and female genitalia agree with those of the latter illustrated by Sohn (2011). Ypsolopha ulingensis Yang is therefore considered to be a junior subjective synonym of costibasella Caradja.

Russia. Primorskii krai: 2♂, Shkotovskii distr., Berezovyi stream, 6 km S Anisimovka, altitude 450 m, 43°07'28"N, 132°47'44"E, 24 August 2002, M. Ponomarenko leg., gen. slide Yps.–81 MP (IBSS).

In the male genitalia Ypsolopha nigrofasciata Yang resembles Ypsolopha yasudai Moriuti, 1977 in the valva bearing a knob at two-thirds of costal margin, a wide rounded excavation between the anterior lobes of the tegumen, medially prominent posterior margin of the uncus and two cornuti of less than one-half the length of the aedeagus.

Ypsolopha nigrofasciata is distinguished by the distinctly constricted median plate of the gnathos with dilated proximal part, the distally conical anterior lobes of the tegumen and the straight basal third of the aedeagus. The forewing is characterized by the longitudinal brown median fascia and the white costal and greyish anal areas (Fig. 3). In Ypsolopha yasudai the median plate of the gnathos has parallel margins, the anterior lobes of the tegumen are broadly rounded distally and the aedeagus is gently arched.

(Fig. 10). Uncus 0.6 times width of vinculum, with triangular projection on posterior margin; socii long, setose, 2.3 times length of median plate of gnathos, tapering towards pointed apex, slightly sinuous. Gnathos constricted just before dilated part of median plate, median plate 0.4 times width of uncus. Tegumen with rounded emargination between anterior lobes, reaching one-half length of tegumen; anterior lobes distally conical. Valva obovate, rounded distally, widest at distal 1/3, considerably narrowed towards base, with distinct knob on costal margin at 2/3 of valvar length; costa relatively narrow, reaching 1/6 length of valva; saccular area one-half width of costa , reaching apex of valva. Vinculum band–like, arched laterally, narrow saccus with parallel margins, slightly shorter than socii. Aedeagus almost straight in basal third and gently arched at middle; coecum about 1/9 length of aedeagus; two cornuti less than one-half length of aedeagus.

China (Hebei), Russia (Far East, first record).

Russia. Primorskii krai: 2♂, 3♀, Khasanskii distr., 14 km SW Slavyanka, Ryazanovka, 42°47'36"N, 131°15'06"E, 16 August 2010, M. Ponomarenko leg. (IBSS).

Russia (Far East, first record), Korea.

This species was previously known only from South Korea. A series of five specimens was collected for the first time in the southernmost part of Primorskii krai.

Holotype: ♂, Russia, Primorskii krai, Ussuriyskii district, Gornotaezhnoe, 43°41'42"N, 132°09'24"E, 28 August 1994, M. Ponomarenko leg., gen. slide Yps.–59 MP (IBSS); labeled by red label with designation “Holotype”. Paratypes (9♂, 1♀): Russia, same locality and collector as in holotype, 20 July 1994, gen. slide Yps.–58 (♂) MP; 29 August 1994, 2 October 1994, gen. slide Yps.–56 (♀) MP; 22 September 1995, gen. slide Yps.–55 (♂) MP; 23 September 1995, gen. slides Yps.–57 (♂) MP, Yps.–60 (♂) MP (IBSS).

Externally the new species is extremely similar to Ypsolopha atrobrunnella Ponomarenko et Sohn, 2011. It can easily be distinguished by the smaller size and the genitalia, especially those of the female, the total length of which (measured from the apex of the papillae anales to the bottom of the corpus bursae) is 1.7 times the length of that in related species. The new species also differs in the male genitalia in the narrower anellus and cornuti with the distal needle-like part 1/6^th the total length of the cornutus (in atrobrunnella almost one-half length of the cornutus), in the distally (from 1/2 to 4/5) almost parallel dorsal and ventral margins of the valva (in atrobrunnella evenly narrowing towards base from dilation at 4/5); in the female genitalia in the absence of a spinose zone in the ductus bursae (in atrobrunnella ductus with a broad band of densely set spines), and a signum with the anterior part wider than the posterior (in atrobrunnella the band–like signum dilated posteriorly).

Adult (Fig. 5).Head covered with appressed elongated narrow dark brown scales with light tips. Antenna filiform; scape dark brown with light grey pecten; each flagellomere dark brown in basal half, white in distal half. Labial palpus porrect and slightly curved upwards, pointed terminally; mainly covered by dark brown scales with white tips; basal segment ventrally white; second segment dorsally and ventrally white, with brown triangular ventral tuft; third segment as long as second, inner surface pale grey. Thorax and tegula dark brown with violet lustre. Foreleg with femur pale grey; tibia greyish brown; each tarsomere dark brown, distally with narrow white ring. Midleg with light grey femur and greyish brown tibia and tarsus. Hindleg with femur and basal two-thirds of tibia light grey, distal third of tibia and tarsus greyish brown; tibial spurs brown dorsally and white ventrally. Forewing length 7.5–8.0 mm (n = 6), wingspan 16.5–17.3 mm (n = 4), sub-trapezoidal, with falcate, obtuse apex and sinuate termen, dark brown with violet lustre; with weakly visible transverse striation; fringe dark brown. Hindwing dark brownish grey, paler towards base; fringe dark grey.

Male genitalia (Fig. 11). Uncus slightly narrower than vinculum, with almost straight posterior margin; socii with long setae, 2.6 times length of median plate of gnathos, tapered towards apex, basal 5/6 with parallel margins, distal part diverging. Gnathos with median plate dilated at middle, about one-half uncus width. Tegumen with dorsal triangular median sclerotization narrowing caudally, divided into pair of anteriorly rounded lobes, dorsal notch about 1/3 length of tegumen. Valva obovate, distally rounded, widest at 4/5, margins almost parallel from 1/2 to 4/5, much narrower towards base; costa very narrow, reaching distal third of valva; saccular area equal in width to costa, about 4/5 length of valva. Vinculum band–like, arched laterally, saccus slightly longer than socii, tapered towards apex. Anellus setose, as wide as basal part of valva. Aedeagus almost straight, with cylindrical apex; coecum 1/6 length of aedeagus, slightly inflated in proximal part and wider than distal part of aedeagus; two long cornuti less than one-half length of aedeagus, each with distal needle–like part of 1/6 length of cornutus.

Female genitalia (Fig. 13). Papilla analis semioval, ovipositor telescopic, intersegmental membrane between IX and VIII almost 5.5 times length of VIII. Apophysis posterior slender, almost reaching apex of papilla analis, thickened anteriorly, 3.7 times length of apophysis anterior; apophysis anterior with Y–shaped base, its ventral branch stretching lateroventrally along anterior margin of VIII. Ventral sclerotization of VIII with sinuous anterior margin, in distal 1/3 divided into pair of lobes, bearing long setae on rounded apex. Ostium slightly wider than one-half of segment VIII; antrum cone–shaped, separated from ductus bursae by colliculum as ring–like sclerotization concave inward dorsally, ventral part of it as narrow band and dorsal one 3 times as wider. Ductus bursae tubular, membranous, 1.4 times length of corpus bursae; bulla seminalis almost length of corpus bursae, with ductus seminalis 1/11 length of bulla seminalis, arising from distal 1/16 of ductus bursae. Corpus bursae ovate, membranous; signum band–like, dilated anteriorly, with two transverse ridges.

Russia (south of Far East).

The specific name, melanofuscella, is derived from two Latin roots melano- and fusc-, collectively meaning “dark brown”, and refers to the forewing coloration of the new species.

Holotype: ♂, Russia, Primorskii krai, Khasanskii district, Mramornaya Mt. foot, 42°34'12"N, 130°48'30"E, 31 July –1 August 2003, M. Ponomarenko leg., gen. slide Yps.–62 MP (IBSS); labeled by red label with designation “Holotype”. Paratypes (41♂, 27♀): Russia. Amurskaya obl.: 2♂, 1♀, 17 km NNE Blagoveshchensk, altitude 160 m, 50°24'01"N, 127°40'20"E, 19, 20 August 2006, gen. slide Yps.–65 MP (♀); 2♂, 1♀, 15 km SSE Svobodnyi, Malaya Sazanka village vic., 51°14'03N, 128°03'54"E, altitude 160 m, 21, 22 August 2006; 1♂, Mikhailovskii distr., 17 km NE Mikhailovka, Zavitaya riv., altitude 166 m, 50°023'23"N, 128°58'19"E, 15 August 2006, M. Ponomarenko leg. (IBSS). Khabarovskii krai: 1♀, Pivan’, 50°31’N, 137°04'E, 18 July 2007, V. Dubatolov, A. Syachina leg. (IBSS). Jewish Autonomous Region: 1♀, Smidovichiskii distr., Zabelovskii reserve, 8–14 July 2001, A. Streltcov, P. Osipov leg. (IBSS). Primorskii krai: 4♂, 1♀, same locality, collecting time and collector as in holotype, gen. slide Yps.–63 (♀) MP; 2♂, 3♀, same locality as in holotype, 2 August 2003; 2♂, 2 km NW Partizansk, Frentzovka village vic., altitude 400 m, 43°12'52"N, 133°01'27"E, 4–5 August 2002, gen. slide Yps.–64 MP; 13♂, 10♀, Ussuriyskii distr., Gornotaezhnoe, 43°41'42"N, 132°09'24"E, 20 July, 1 September, 1 October 1994; 17, 22, 23 August, 10, 21, 22, 23 September 1995, gen. slide Yps.–66 (♂) MP; 2♂, 42 km W Ussuriisk, 4 km N Monakino, 43°46'50"N, 131°26'29"E, altitude 290 m, 23 April 2003; 1♀, 5 km E Nikolo-Lvovskoe village, 43°52'16"N, 131°25'14"E, altitude 174 m, 2 September 2002, gen. slide Yps.–67 MP; 1♂, 1♀, 29 km SE Ussuriisk, 43°37'48"N, 132°13'44"E, 25 August 2001, M. Ponomarenko leg.; 1♂, 4, 5 km SE Okeanskaya, 43°13'06"N, 132°03'26"E, 16 September 1993, E. Beljaev leg.; 1♀, Chernigovskii distr., 42 km S Spassk-Dalnii, Gribnoe village vic., 44°15'29"N, 132°44'51"E, 25 August 1998, gen. slide Yps.–68 MP; 5♂, 4♀, Khasanskii distr., 14 km SW Slavyanka, Ryazanovka, 42°47'36"N, 131°15'06"E, 9–10 September 1992; 23 August 1997; 19, 20, 21 September; 22 October 2008; 16 August 2010; 5♂, 2♀, Gamov Peninsula, Srednyaya Inlet, 42°35'18"N, 131°12'48"E, 24 July 1997, 8, 9, 13, 14 August 2009; 1♂, Gamov Peninsula, Gorshkova Inlet, 42°40'17"N, 131°12'48"E, 30 August 1997, M. Ponomarenko leg. (IBSS).

The new species resembles Ypsolopha leuconotella (Snellen, 1884) in the genitalia of both sexes: in the male in the shape of the valva with parallel margins in the distal half, the gnathos with a wide, rounded median plate, the almost straight aedeagus with indistinct cornuti of less than half the length of the aedeagus; and in the female in the presence of a scobinate zone in the ductus bursae. The new species differs from leuconotella in the male genitalia in the narrower base of the valva, which is less than one-half its greatest width (in leuconotella equal to one-half of greatest width), the rounded emargination between the anterior lobes of the tegumen (in leuconotella the emargination between the anterior lobes of the tegumen is triangular) and the inflated basal part of the aedeagus (caecum) (aedeagus narrowed basally in leuconotella). The new species can also be separated in the female genitalia by a scobinate zone in the ductus bursae of slightly over one-half the ductus length (in leuconotella the ductus with scobinate inner surface except 1/10 just following antrum), and a large signum, longer than two-thirds of corpus bursae (in leuconotella slightly less than one-half of corpus bursae length).

Adult (Fig. 6).Frons and vertex covered by closely fitting greyish yellow scales. Occiput with appressed elongated scales mainly greyish yellow and speckled with dark before light tips. Antenna filiform; scape greyish yellow with light yellow pecten; each flagellomere with light yellow basal and dark brown distal half; ventrally ciliated. Labial palpus porrect and slightly curved upwards, terminally pointed; basal segment white; second segment basally white, with triangular greyish yellow ventral tuft, speckled with brown; third segment as long as second, dorsally white, ventrally dark brown with scattered white scales. Thorax and tegula brownish grey. Foreleg with white femur and tibia; each tarsomere with narrow white distal ring, irrorated with brown. Midleg with white femur, tibia, ventral side of first (basal) tarsomere and spurs, second and following tarsomeres speckled with brown, lighter laterally and with narrow white ring distally. Hindleg with white femur, tibia, basal tarsomere and spurs; 2nd–5th tarsomeres speckled with brown and with white ventral margin. Forewing length 7.5–8.0 mm (n = 6), wingspan 16.5–17.3 mm (n = 4), sub-trapezoidal, with falcate, obtuse apex and sinuate termen. Ground colour of forewing greyish yellow irrorated with brown and greyish scales; 1/6th of costal margin brown; large greyish brown spot on dorsal half at 1/4, wide oblique brown band from base of R1 to middle of dorsal margin, large semi-oval greyish brown spot at end of cell, smaller concolorous spot dorsad and distad of latter, dorsal margin of wing and tornus greyish brown, six indistinct small strokes on costal margin from middle to 7/8; fringe greyish yellow. Hindwing dark brownish grey, darker towards apex; fringe brownish grey basally and yellow distally.

Male genitalia (Fig. 12). Uncus equal to vinculum in width, with almost straight posterior margin; socii 2.3 times length of median plate of gnathos, with long setae, curved outwardly before pointed apices. Median plate of gnathos with parallel lateral margins, one-third width of uncus. Tegumen divided into pair of anteriorly angulate lobes, anterior margin with triangular median emargination, not exceeding 1/4 of tegumen length. Valva more or less obovate, distally rounded and considerably narrowed towards base, with almost straight costal margin and rounded saccular margin; costal and saccular area equal in width, reaching 4/5 length of valva. Vinculum band–like, laterally with small triangular plates; saccus tapering towards apex, almost as long as socii. Anellus setose and wider than basal part of valva. Aedeagus almost straight, with cylindrical apex; coecum slightly longer than 1/4 length of aedeagus, slightly inflated in proximal part and wider than distal part of aedeagus; two long cornuti less than one-half length of aedeagus, each with distal needle–like part, less 1/5 total length of cornutus.

Female genitalia (Fig. 14). Papilla analis semi-oval, ovipositor telescopic, intersegmental membrane between IX and VIII almost four times length of VIII. Apophysis posterior slender, slightly thickened anteriorly, 2.75 times length of apophysis anterior; apophysis anterior with Y–shaped base, its ventral branch extending lateroventrally along anterior margin of VIII. Segment VIII, its ventral sclerotization, ostium and antrum very similar to Ypsolopha melanofuscella sp. n. Ventral sclerotization of VIII with sinuous anterior margin, in distal 1/3 divided into pair of rounded lobes, bearing long setae on rounded apex. Ostium slightly wider than one-half of segment VIII; antrum cone–shaped, separated from ductus bursae by narrowing and ring–like colliculum concave inward dorsally, its ventral part as narrow band and dorsal one 3 times wider. Ductus bursae tubular, membranous, 1.7 times length of corpus bursae, dilated anteriorly; anterior part with dense minute scobinations on inner surface from 2/5 to 1/14 length of ductus. Bulla seminalis shorter than corpus bursae, with ductus seminalis 1/3 length of bulla seminalis, arising from ductus bursae just near colliculum. Corpus bursae ovate, membranous; signum large band–like, comparatively wide and long, more than 2/3 length of corpus bursae, with two transverse ridges.

Russia (south of Far East).

The species name, straminella, is derived from the Latin stramineus, meaning “straw”, or “pale yellow” and refers to the colour of the forewing of the new species.