Biston mediolata, Jiang, Nan, Xue, Dayong & Han, Hongxiang, 2011

Jiang, Nan, Xue, Dayong & Han, Hongxiang, 2011, A review of Biston Leach, 1815 (Lepidoptera, Geometridae, Ennominae) from China, with description of one new species, ZooKeys 139, pp. 45-96 : 57-60

Biston mediolata sp. n. Figs 21-2476103121

Biston contectaria Walker, sensu Xue, 1992a; in Liu, Iconography of Forest Insects in Hunan China: 880.

Description.

Head.

Antennae about one-third length of forewing, bipectinate in basal three-fifths, filiform in terminal two-fifths, rami short, length of longest ramus about the same as diameter of antennal shaft; filiform in female. Frons not protruding, smooth-scaled, with basal half white, upper half black. Labial palpus black, small, not extending beyond frons. Vertex white.

Thorax. Dorsum greyish white, scattered with black scales. Patagia and tegulae greyish white, mottled with black scales, pale yellow distally. Posterior margin of metanotum with yellow scales medially. Hind tibia with two pairs of spurs in male, slightly dilated, without hair-pencil. Forewing length: male 32-34 mm; female 42 mm. Forewing outer margin almost straight, hindwing round. Wings white, with pale grey striation. Pattern of forewing: antemedial line black, almost straight anteriorly, distinct, accompanied by a pale yellow band basally; medial line greyish yellow, indistinct; postmedial line black, distinct, acutely protruding outwards between M1 and M 3, shallowly protruding outwards between CuA2 and 1A + 2A, sometimes internally dentate on veins; a pale yellow band distally of postmedial line, diffused with black patches; terminal line black; fringe pale yellow mixed with black; discal spot present as pale grey dot, indistinct. Hindwing with basal line black, distinct; medial line only distinct near anal margin; postmedial line black, bluntly protruding outwards between M1 and M3, sometimes appearing as black serrations on veins; a pale yellow band distally of postmedial line; terminal line indistinct; fringe and discal spot similar to those of forewing. Underside white; transverse lines dark grey, similar to those of forewing, discal spot black, heavy, on hindwing smaller than on forewing.

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 two-fifths 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.

Female genitalia.

Ovipositor with apophyses posteriores elongate. Lamella postvaginalis small and almost triangular. Ostium bursae sclerotized. Ductus bursae striated longitudinally, short. Corpus bursae long, curved medially, swollen anteriorly, bearing a signum; signum long elliptic with marginal spines.

Diagnosis.

The wing pattern of this species is similar to that of Biston 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 M1 and M3; 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 CuA2 and 1A + 2A, while in Biston contectaria , it is straight; the protrusion between M1 and M3 of the hindwing postmedial line is round but sharply angled in Biston 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 Biston contectaria . The female genitalia are similar to those of Biston 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 Biston panterinaria by presence of the lamella postvaginalis.

Type material.

Holotype(IZCAS), ♂, CHINA, Hubei: Xingshan, Longmenhe, 1200 m, 18.VII.1993, coll. Song Shimei. Paratypes, CHINA, Shaanxi(IZCAS): Liuba, Miaotaizi, 1470-1550 m, 1-2.VII.1999, coll. He Tongli, 2♂. Gansu(IZCAS): Kangxian, Qinghe Linchang, 1450-1650 m, 15.VII.1998, coll. Yao Jian, 1♂; Wenxian, Dianba, 23.VI.1992, coll. Wang Hongjian, 1♂. Hubei(IZCAS):Xingshan, Longmenhe, 1260-1350 m, 17-23.VI., 14-21.VII.1993, coll. Huang Runzhi, Song Shimei and Yao Jian, 11♂; Hefeng, 1240 m. 21-31.VII.1989, coll. Li Wei, 4♂; Hefeng, Fenshuiling, 1240 m, 1989.VII.29, coll. Li Wei, 1♀; Badong, 19.V.1989, coll. Li Wei, 1♂. Hunan(IZCAS): Chenzhou, Guanlisuo, 8.VII.1969, 1♂. Fujian(IZCAS): Mt. Wuyi, Sangang, 740 m, 25.V.-30.VI.1960, coll. Zhang Yiran, 2♂; Mt. Wuyi, Sangang, 10.V.1981, coll. Wang Jiashe, 1♂; Mt. Wuyi, Sangang, 14.VI.1983, coll. Wang Linyao, 1♂. Guangxi (IZCAS):Nanningqu, Linkesuo, 110 m, 17.IV.1984, 1♂; Mao’ershan, 1600 m, 15.VII.1985, coll. Fang Chenglai, 1♂; Jinxiu Shengtangshan, 900-1900 m, 29.VI.2000, coll. Li Wenzhu, 1♂; Jinxiu, Linhai, Shanzhuang, 1000 m, 2.VII.2000, coll. Li Wenzhu, 3♂. Sichuan(IZCAS):Mt. Emei, Qingyinge, 800-1000 m, 22.V., 21-26.VI., 11-16.VII.1957, coll. Huang Keren and Zhu Fuxing, 7♂. Hubei (ZFMK): Wufeng, Yizhuxiang, 1560 m, VI.1998, coll. Wang and Li 1♂. Fukien[Fujian] (ZFMK): Kuatun, 2300 m, 28.V., 1.VI.1938, coll. J. Klapperich, 2♂. Hainan (ZFMK): Wuzhishan, 1600 m, VII.1998, coll. Yin and Wang, 6♂. VIETNAM (ZFMK): Mt. Fan-si-pan, 1600-1800 m, 8-29.V.1993, coll. Sinjaev and Simonov, 2♂.

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.

Distribution.

China (Shaanxi, Gansu, Hubei, Hunan, Fujian, Hainan, Guangxi, Sichuan), Vietnam.