A review of Biston Leach, 1815 (Lepidoptera, Geometridae, Ennominae) from China, with description of one new species

Abstract The genus Biston Leach, 1815 is reviewed for China. Seventeen species are recognized, of which Biston mediolata sp. n. is described. Biston pustulata (Warren, 1896) and Biston panterinaria exanthemata (Moore, 1888) are newly recorded for China. The following new synonyms are established: Biston suppressaria suppressaria (Guenée, 1858) (= Biston suppressaria benescripta (Prout, 1915), syn. n. = Biston luculentus Inoue, 1992 syn. n.); Biston falcata (Warren, 1893) (= Amphidasis erilda Oberthür, 1910, syn. n. = Amphidasis clorinda Oberthür, 1910, syn. n. = Biston emarginaria Leech, 1897, syn. n.); Biston panterinaria panterinaria (Bremer & Grey, 1853) (= Biston panterinaria abraxata (Leech, 1889), syn. n. = Biston panterinaria lienpingensis (Wehrli, 1939), syn. n. = B. panterinaria szechuanensis (Wehrli, 1939), syn. n.). Biston falcata satura (Wehrli,1941), comb. n. is proposed. A key to Chinese Biston and diagnoses for Chinese species are provided. Illustrations of external features and genitalia are presented.

introduction Leach (1815) established the genus Biston Leach, 1815 with three species, Geometra prodromaria Denis & Schiffermüller, 1775, Phalaena (Geometra) betularia Linnaeus, 1758 and Phalaena hirtaria Clerck, 1759. Geometra prodromaria was designated as the type species of Biston by Westwood (1840) and was later found to be a junior synonym of Phalaena strataria (Hufnagel, 1767) by Prout (1915). Phalaena hirtaria was designated as the type species of Lycia Hübner, 1825 by Hulst (1896). Phalaena betularia is still treated as a member of Biston. Hampson (1895), as the first author, presented a wider concept of Biston and included Eubyjodonta Warren, 1893, Amraica Moore, 1888, Buzura Walker, 1863and Cusiala Moore, 1887 in the genus Biston. Prout (1915) also included the species of Eubyjodonta in Biston, but did not explicitly state Eubyjodonta as a synonym. Subsequently, this genus was considered as a subgenus of Biston by Wehrli (1941). In addition, Prout (1915) treated Buzura as a separate genus, and regarded Amraica and Blepharoctenia Warren, 1894 as different sections of Buzura according to the structure of male antennae, and moved Cusiala to his very broadly defined "genus" Boarmia. Inoue (1982aInoue ( , 1985 established the broader concept of Biston by examining external and genital characters of the Palaearctic and the East Asiatic species. He treated Buzura as a junior synonym of Biston and raised Amraica to generic level. Sato (1996) also considered Culcula Moore, 1888 as a junior synonym of Biston. Parsons et al. (1999) summarized the previous works, and besides the generic names mentioned above, they also included Epamraica Matsumura, 1910 and Eubyja Hübner, 1825 as junior synonyms of Biston. Rindge (1975Rindge ( , 1985 summerized New World Bistonini and gave a valuable diagnosis for the genus Biston. Holloway (1994) proposed a very broad concept of the tribe Boarmiini which also subsumed the previously separate tribe Bistonini, and provided the diagnostic characters for the genus Biston.
Biston indeed has some typical features in common with the Boarmiini: the postmedial lines of both wings often protrudes outwards between M 1 and M 3 ; in the male genitalia, the socii are usually absent; the valva has a strong cucullus. However, Biston also has some features atypical for Boarmiini: a fovea is absent in the male forewing; in the male genitalia, the valva is simple, without any ornamentation (Holloway 1994;Pitkin 2002;Viidalepp et al. 2007;Young 2008).
Here, we divide the Chinese Biston into three species groups based on morphological characters. Group I includes the "typical" species of Biston. Group II includes B. brevipennata Inoue, 1982 and the species which were treated in the subgenus Eubyjodonta of Biston by Wehrli (1941). Group III includes B. perclara (Warren, 1899), B. thibetaria (Oberthür, 1886) and B. panterinaria (Bremer & Grey, 1853) which was considered slightly different from the typical species of Biston by Sato (1996).
The purpose of this paper is, to review all known Chinese Biston species, to determine their diagnostic characters, to develope a key for their determination and to provide illustrations of external features and genitalia; furthermore, one new species, B. mediolata sp. n., will be described, B. pustulata (Warren, 1896) will be recorded as new for the fauna of China and several new synonyms and a new combination will be proposed. This results, to our present knowledge, in 17 species and nine subspecies of Biston for the fauna of China and 52 species with 33 subspecies worldwide.

Material and methods
Specimens of Biston were obtained from Institute of Zoology, Chinese Academy of Sciences, Beijing, China (IZCAS) and Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany (ZFMK). The other museums cited here, where types are deposited, are the Natural History Museum, London, United Kingdom (BMNH), the Linnean Society of London, United Kingdom (LSL), the Zoologische Staatssammlung Muenchen, Munich, Germany (ZSM) and the Zoological Institute, Russian Academy of Sciences, Saint-Petersburg, Russia (ZISP). Terminology for wing venation followed the Comstock-Needham System (Comstock 1918) as adopted for Geometridae by Scoble (1992) and Hausmann (2001), and that of the genitalia was based on Pierce (1914), Klots (1970) and Nichols (1989). Photographs of adult moths and their genitalia were taken with digital cameras. Composite images were generated using Auto-Montage software version 5.03.0061 (Synoptics Ltd). The plates were compiled using Adobe Photoshop software. margin smooth, sometimes concave between M 1 and M 3 or protruding between M 1 and CuA 1 . Wings white, pale yellow or greyish brown, transverse lines black, brown or white. Pattern of forewing: antemedial line slightly waved, often accompanied by a band basally; medial line waved, usually inconspicuous; postmedial line waved or dentate, sometimes protruding outwards between M 1 and M 3 and between CuA 2 and 1A + 2A, often accompanied by a band posteriorly; submarginal line sometimes indistinct; terminal line sometimes appearing as a series of short stripes between veins; discal spot black or grey, shortly strip-like, dot-like or elliptic, pale-centred. Hindwing sometimes with basal line; medial line often indistinct, sometimes double; postmedial line waved or dentate, sometimes protruding outwards between M 1 and M 3 ; terminal line similar to those of forewing; discal spot sometimes smaller and less conspicuous than on forewing. Terminal spots occasionally present on both wings, wedge-shaped. Underside paler, transverse lines often similar to those of dorsal surface.
Venation. Forewing: Sc free, R 1 and R 2 usually stalked (separate in B. thoracicaria), diverging before anterior angle of cell; R 2 sometimes connected by a short transverse bar with R 3-4 or R 3-5 ; R 3-5 before or from anterior angle of cell, not stalked with M 1 ; M 1 from anterior angle of cell; M 3 from posterior angle of cell; CuA 1 before posterior angle of cell. Hindwing: Sc+R 1 close to cell less than onehalf length of cell; Rs before anterior angle of cell; M 1 from anterior angle of cell; M 2 absent; M 3 from posterior angle of cell; CuA 1 before or from posterior angle of cell; 3A absent.
Abdomen. Dorsum scattered with transverse lines or dots, sometimes with anal tuft. Third sternite of male abdomen without setal patch. Intersegmental membrane between abdomen and genitalia densely covered with elongate scales which partly developed to spines in a few species.
Male genitalia. Uncus short and broad, ratio of length to basal width variable, often bifurcate terminally, sometimes bifurcation very shallow or on ventral side below apex, so the latter apparently square or round. Arms of gnathos connected medially, with median process robust or slender, round, acute or square terminally. Valva simple; costa sclerotized, straight or incurved, with terminal half often broadened, bearing long setae from center to apex; sacculus sometimes sinuous. Saccus round or semicircular. Juxta well developed, pointed, or round or flat apically, sometimes elongate, without lateral brushes of long setae, except in B. melacron Wehrli, 1941. Aedeagus often cylindrical, sclerotized dorsally; vesica usually wrinkled, scobinate, with or without cornuti; shape of cornuti various.
Diagnosis. The genus Biston resembles Cusiala Moore and Iulotrichia Warren in: the postmedial lines of both wings often protrudes outwards between M 1 and M 3 ; the apex of the uncus is often bifurcated. But Biston differs from Cusiala and Iulotrichia in the following characters: the forewing fovea of the male is absent in Biston but present in Cusiala and Iulotrichia; in the male genitalia, the aedeagus vesica has numerous, very small, spine-like cornuti, arranged as two pair of longitudinal combs in Cusiala and Iulotrichia, which is absent in Biston. The members of Biston also resemble Lycia Hübner, 1825 andCochisea Barnes &McDunnough, 1916, both of which belong to the former Bistonini. But both of these genera can be distinguished from Biston by the single pair of spurs on the hind tibia, as well as apterous or brachypterous female in Lycia, and absence of the tongue in Cochisea.
Distribution. Holarctic, Oriental, and Ethiopian regions. Biological notes. The larva is often twig-like with the characteristic 45 degree resting posture and an obtusely cleft head (Holloway 1994). Singh (1953) recorded the larva of B. suppressaria (Guenée, 1858). Issiki et al. (1977) illustrated the larva of B. robustum Butler, 1879. Yamamoto et al. (1987 described and illustrated the larvae of B. betularia (Linnaeus, 1758), B. robustum, B. regalis (Moore, 1888) andB. panterinaria. Wagner (2001) recorded the larva of B. betularia. Sato (2001) described the larva of B. marginata Shiraki, 1913. Leong (2009 from Inoue 1965;Holloway 1994;Zhang 1994;Parsons et al. 1999;Sato 2001;Robinson et al. 2004). Patočka (2004) and Patočka and Turcani (2005) construct a key for the pupae of central European species. Nakamura (2004) described and gave a key for the pupae of Japanese species. wing postmedial line bilobedly protrudes between M 1 and M 3 , and slightly protrudes outwards between CuA 2 and 1A + 2A. But it can be distinguished from B. marginata by the following characters: the hindwing outer margin is concave between M 1 and M 3 , whereas it is evenly round in B. marginata; the transverse lines are black but dark brown in B. marginata; the hindwing postmedial line is waved after M 3 , but straight in B. marginata; the transverse lines on the underside of the wings are more conspicuous.
The most distinct differences are in the male genitalia: the apex of the uncus is broader and bifurcated, whereas it is narrower and round in B. marginata; the median process of the gnathos is broader and round terminally, while in B. marginata, it is slenderer and acute apically; the setose area of the valva is much weaker; the juxta is narrower, and sharply pointed apically, while in B. marginata, it is broader and round apically; the cornutus is shortly digitiform, but is thornlike in B. marginata. In the female genitalia (Inoue 1977), the signum is much longer than in B.  (1965)) Diagnosis. The diagnostic characters of external morphology of the species can be seen in the previous species. The male genitalia of the species are close to those of B. suppressaria. But it can be distinguished from the latter by the following characters: the vesica is less strongly sclerotized posteriorly; the cornutus is small and spine-like but absent in B. suppressaria. The female genitalia are similar to those of B. betularia, but they differ in the following characters: the ductus bursae is shorter and the antrum is absent; the corpus bursae is almost even in width, while in B. betularia it is enlarged, wrinkled and weakly sclerotized posteriorly, narrow medially and swollen anteriorly; the signum is oval with several marginal spines, but a transverse bar in B. betularia. Distribution. China (Zhejiang, Jiangxi, Hunan, Fujian, Taiwan, Guangdong, Guangxi, Chongqing, Yunnan), Japan, Vietnam.
Abdomen. First abdominal segment greyish white with black basal margin, remaining segments yellowish brown, scattered with black dots. Setal patch absent on third sternite of male abdomen.
Male genitalia. Uncus somewhat trapeziform, about three-fifths length of basal width. Gnathos with median process short and broad, round terminally, about twofifths length of uncus. Valva simple, broad at base, gradually narrowing apically, about twice as long as basal width; costa sclerotized, incurved medially, expanded with particularly dense setae basally. Saccus round, about one-third length of basal width. Juxta short and broad, almost round. Coremata not developed. Aedeagus cylindrical, sclerotized dorsally; vesica scobinate, cornutus shaped as a narrow band.
Diagnosis. The wing pattern of this species is similar to that of B. contectaria as follows: the forewing outer margin is almost straight anteriorly; the antemedial line is black, broad and almost straight; the postmedial line acutely protrudes between M 1 and M 3 ; the medial lines of both wings are greyish yellow and indistinct; pale yellow bands are present basally of the forewing antemedial line and distally of the postmedial line of both wings; the hindwing basal line is black and distinct. But this species is smaller and can be distinguished by the following characters: the postmedial lines of both wings are narrower; the forewing postmedial line weakly protrudes outwards between CuA 2 and 1A + 2A, while in B. contectaria, it is straight; the protrusion between M 1 and M 3 of the hindwing postmedial line is round but sharply angled in B. contectaria; the discal spots on the underside of both wings are larger and heavier. In the male genitalia: the much broader uncus and valva of the new species are distinctly different from B. contectaria. The female genitalia are similar to those of B. panterinaria as follows: the apophyses posteriores are long; the ostium bursae is sclerotized; the ductus bursae is very short; the corpus bursae is curved medially; the signum is elliptic and narrow. But it can be distinguished from B. panterinaria by presence of the lamella postvaginalis. Etymology. The specific name is from the Latin prefix medio-and the word latus, which means medially and broad, refers to the shape of the valva. Diagnosis. The external characters of this species are close to those of B. suppressaria and B. inouei Holloway, 1994 (Borneo), but it can be distinguished from those species by the following differences: this species (length of forewing: 27-28 mm in male) is larger than B. suppressaria and smaller than B. inouei; the protrusion between M 1 and M 3 of the forewing postmedial line is relatively acute, but blunt or bilobed in B. suppressaria and B. inouei; the hindwing basal line is more distinct in B. contectaria and B. inouei; the projection between M 1 and M 3 of the the hindwing postmedial line is relatively acute in B. contectaria and B. suppressaria, but blunt in B. inouei. In the male genitalia, the apex of the uncus is broader than that of B. suppressaria and B. inouei, and is almost not bifurcated; the median process of the gnathos is shorter and round distally, whereas it is longer and pointed in B. suppressaria and B. inouei; the costa and the ventral margin of the valva are curved, while those of B. suppressaria and B. inouei are less curved or even incurved or concavely curved; the costa is expanded and has dense setae basally, while it is straight in B. suppressaria and B. inouei; the juxta is shorter and less pointed apically. Diagnosis. The external characters of this species are close to those of B. contectaria, but it can be distinguished from that species by the following differences: the wings are pale yellow but white in B. contectaria; the forewing postmedial line is much narrower and protruding outwards between CuA 2 and 1A + 2A, while in B. contectaria, it is broader and without such a protrusion; the discal spot on the hindwing upperside is large, round, black, while in B. contectaria it is almost absent; the discal spots on the underside of both wings are larger and heavier. The male genitalia are close to those of B. suppressaria, but it can be distinguished by the square apex of the juxta, the shorter median process of the gnathos and the presence of a cornutus which is a short spinous patch. The female genitalia are similar to those of B. suppressaria. But it differs in that the corpus bursae is coiled anteriorly; the signum is longer and narrower; the ostium bursae is more strongly sclerotized.

Description.
Head. Male antennae about two-fifths length of forewing, bipectinate in basal two-thirds, filiform in terminal one-third, rami long, length of longest ramus about three and half times diameter of antennal shaft. Frons not protruding, smoothscaled, with basal half pale yellow, upper half black. Labial palpus black, small, pale yellow apically, not extending beyond frons. Vertex pale yellow.
Thorax. Dorsum white-dotted with black scales. Patagia and tegulae white, mottled with black scales, yellow apically. Posterior margin of metanotum with two pairs of pale yellow spots. Hind tibia with two pairs of spurs in male, slightly dilated, without hair-pencil. Forewing length: male 29 mm. Forewing outer margin straight, hindwing round. Wings greyish white, dotted with pale grey scales. Pattern of forewing: antemedial line black, slightly waved, distinct, accompanied by a pale yellow band basally; medial line pale yellow, indistinct; postmedial line black, distinct, bilobedly protruding outwards between M 1 and M 3 , then incurved, protruding outwards between CuA 2 and 1A + 2A; a pale yellow band distally of postmedial line; black patches present between M 1 and CuA 1 distally of postmedial line and reaching outer margin between M 1 and M 3 ; submarginal line white, dentate; terminal line a series of short black strips between veins; fringe yellow mixed with black; discal spot present as grey dot. Hindwing with basal line black; medial line pale yellow, indistinct; postmedial line black, acutely protruding outwards between M 1 and M 3 ; a pale yellow band distally of postmedial line, scattered with black scales; submarginal line and fringe similar to those of forewing; terminal line less distinct than that of forewing; discal spot smaller. Underside pale yellow, transverse lines dark grey, similar to those of upper side, discal spots black, more distinct than those of upper side.
Abdomen. Dorsum greyish white, dotted with black scales, anal tuft pale yellow. Setal patch absent on third sternite of male abdomen.
Male genitalia. Uncus with bifurcate apex, about two-thirds length of basal width. Gnathos with median process slender, pointed terminally, equal to length of uncus. Valva compressed, about twice as long as basal width; costa sclerotized, straight, bearing long setae from center to apex. Saccus semicircular. Juxta long and broad, terminal half triangular, with pointed apex. Coremata not developed. Aedeagus cylindrical, striated posteriorly; vesica scobinate, without cornuti.
Biston luculentus Inoue, 1992, described from SE. Thailand, is similar to B. suppressaria benescripta, but has the transverse lines even more clearly expressed (e.g. see fig. 37 which is almost identical with B. luculentus). Like B. suppressaria benescripta, also the B. luculentus form occurs sympatrically with typical B. suppressaria suppressaria or with B. suppressaria benesparsa Wehrli, the latter being a rather rare form, at many places. Also at the type locality of B. luculentus (Prov. Chanthaburi, Khao Soi Dao) it occurs together with typical suppressaria (coll. ZFMK) Comparison of the genitalia of the two revealed no differences. Thus we follow Stüning (in litt.) and synonymize B. luculentus with B. suppressaria. Besides, we also believe that the strange, almost patternless female figured by Inoue (1992) Prout, 1915, in Seitz, Macrolepid. World, 4: 359, pl.19: h. Diagnosis. The wing pattern of this species is similar to that of B. exalbescens Inoue, 2000 (Philippines) as follows: the forewing postmedial line is weakly waved, broadly protruding outwards between R 5 and M 3 and below CuA 2 ; the hindwing outer margin is concave between M 1 and M 3 ; the hindwing postmedial line protrudes outwards between M 1 and M 3 ; dark brown bands are present basally of the forewing antemedial line and distally of the postmedial line of both wings, and usually absent at apical area and between M 3 and CuA 1 of the forewing. But the species can be distinguished from B. exalbescens by the following characters: the forewing antemedial line is thinner, the dark brown band basally of it is narrower; the medial lines of both wings are less conspicuous. In the male genitalia, it differs in the much stronger central setose area of the valva; the median process of the gnathos is spatulate terminally, but pointed in B. exalbescens; the juxta is longer and narrower; the vesica with two cornuti, a basal, oval plate with a lateral tooth and an elongate, sclerotized, spined fold. The female genitalia of this species are close to that of B. betularia, but it has a nearly triangular lamella postvaginalis, which is absent in B. betularia; the ductus bursae is broader and sclerotized, without antrum; the corpus bursae is pouched, but enlarged posteriorly and narrow medially in B. betularia; the signum is almost oval, but bar-like in B. betularia.

Biston brevipennata
Diagnosis. The present species can be distinguished from the other species in group II by the following characters: smaller sized (length of forewing: 23-25 mm in male); the forewing outer margin is less waved; the band basally of the forewing antemedial line is much thinner; the speckles scattered on the wings are dark brown, not black. In the male genitalia, the apex of the uncus is broader and shallowly bifurcated but narrower and round in the others; the juxta is more sharply pointed at tip. Material examined. CHINA, Tibet (IZCAS): Gyirong, 18.VI.-23.VII.1984, coll. Yan Zhaoxing and Pu Qiongzhi, 2♂;Zham, 2200m, 25.VI.1975 Distribution. China (Tibet), Nepal.
Biston quercii (Oberthür, 1910) http://species-id.net/wiki/Biston_quercii Figs 44,45,83,110 Amphidasis quercii Oberthür, 1910, Études Lépid. comp., 4: 676, pl. 51, fig. 433. Holotype ♀, China: Sichuan, Tien-Tsuen. (ZFMK) Biston quercii: Prout, 1915, in Seitz, Macrolepid. World, 4: 359. Biston (Eubyjodonta) quercii : Wehrli, 1941, in Seitz, Gross-Schmett. Erde, 4 (Suppl.): 434, pl. 36: f. Diagnosis. The wing pattern of this species is similar to that of B. falcata as follows: the forewing antemedial line is black, slightly waved; the postmedial lines of both wings are black and dentate; broad brown bands are present basally of the forewing anteme-dial line and distally of the postmedial lines of both wings; the speckles scattered on the wings are black, and often gather to a black patch basally of the submarginal lines; the hindwing medial line is black and double. But it can be distinguished by the following characters: the outer margins are more undulating, there are distinct marginal processes in the centre of both wings, absent in B. falcata; the hindwing discal spot is present. The male genitalia are similar to those of B. falcata as follows: the apex of the uncus is round; the median process of the gnathos is broad and round apically; the juxta is long, narrow, acute and with a longitudinal arris apico-ventrally; the cornutus is shaped as a spinous patch. But this species is characterized by the narrower juxta and the longer spines of the cornutus.

Diagnosis.
The diagnostic characters of the external mophology and the male genitalia can be seen in the preceding species. In the female genitalia, the species can be distinguished from other congeners by the following characters: the apophyses posteriores are short, about twice the length of apophyses anteriores; the ductus bursae is sclerotized and striated longitudinally, about one-third the length of corpus bursae; the corpus bursae is weakly sclerotized and striated posteriorly; the signum usually consists of two small separate sclerotized patches. obvious that B. emarginaria (only females known) and Amphidasis clorinda (female holotype known only) are all females of Amphidasis erilda. The external and genital features of Amphidasis erilda, on the other hand, turned out to be almost identical or fall within the range of variation of B. falcata. Thus we treat B. emarginaria, Amphidasis erilda, Amphidasis clorinda as junior synonyms of B. falcata. B. erilda satura, as described by Wehrli (1941), is treated as a valid subspecies, but has be combined newly with B. falcata, as explained above. Thus, two Chinese subspecies of B. falcata are B. falcata falcata (Warren, 1893) and B. falcata satura (Wehrli, 1941). In China, the former is distributed in Sichuan, Yunnan and Tibet (Figs 46,[48][49][50][51][84][85][86]112,125,126), the latter is distributed in Shaanxi,Ningxia and Gansu (Figs 47,52,53,87,88,113,127). There are some intraspecific variations between individuals of B. falcata, for example, in the the male genitalia, the apical part of the valva varies from broad to narrow in the same region, such as Gansu (Figs 87, 88) and Tibet (Figs 85, 86); in the female genitalia, the signum usually consists of two small separate sclerotized patches, sometimes there is only one signum or the signum is very tiny, and the position of the signum is variable individually.

Biston perclara (Warren, 1899)
http://species-id.net/wiki/Biston_perclara Fig. 54 Blepharoctenia perclara Warren, 1899, Novit. zool., 6: 49 (1914)) Epamraica bilineata Matsumura, 1910, Thousand Insects Japan, (Suppl.)   Diagnosis. This species is very distinct and is easily recognizable by the thick black lines and yellowish green bands placed basally of the antemedial line of the forewing and distally of the postmedial lines of both wings, the large, black ringed and palecentred discal spots on both wings, as well as the black-belted abdomen and the fresh yellow anal tuft. The male genitalia of B. thibetaria are close to those of B. panterinaria: the apex of the uncus is bifurcated and about four-fifths as long as the basal width; the median process of the gnathos is short and round apically; the valva is broad basally and narrow apically; the ventral margin of the valva is slightly sinuous; the juxta has a deep incision at the middle on the posterior margin; the cornutus is stick-like; a narrow sclerotized band is present on lateral side of the aedeagus. But it can be distinguished from that species by the strongly rounded basal half of the valva. The female genitalia of the species are close to those of B. panterinaria as follows: the ostium bursae is weakly sclerotized; the ductus bursae is very short; the corpus bursae is curved medially, striated in the posterior half and enlarged at tip; the signum is oval and with marginal spines. It differs in having an oval lamella postvaginalis, which is absent in B. panterinaria.