Metrocoris nigrofascioides Chen & Nieser, 1993 (Figs. 16, 17, 38, 77–79) Metrocoris nigrofascioides Chen & Nieser, 1993: 34–35, Figs. 90, 97, 105 (type locality: Fang, Chiang Mai, Thailand); Zettel & Chen, 1996: 152, 177 (records from Vietnam). Material examined. VIETNAM: Thanh Hoa Prov.: 1 male (apt), 1 male, 1 female (mpt), Ben En N’Park, Nhu Xuan, Son Binh, Khe Cay Khe stream, site 1, coll. Pham T.D., 01 March 2013, BE1304 (ZMHU). Quang Binh Prov.: 1 male (apt), Phong Nha, upstream of Thac Xoi waterfall, coll. Tran A.D., 15 July 2004, DY0407 (ZRC); 4 males, 2 females (apt), Phong Nha, a stream 1 km behind Forest Ranger station 4, coll. Tran A.D., 16 July 2004, DY0409 (ZMHU). Da Nang Prov.: 4 males (apt), Ba Na - Nui Chua foothills, Suoi Lanh, coll. Tran A.D. & Tan H.H., 01 March 2005, THH05-25 (ZRC). Kon Tum Prov.: 1 male, 3 females (apt.), stream 2 km inside Chu Mom Ray Nature Reserve, 635 m asl, 14°25′55″N, 107°42′46″E, water temp. 21°C, 4 March 2001, CL 4277, coll. J.T. Polhemus & P. Nguyen (USNM); 2 females (apt), stream 63 km NE. of Kontum on Hwy. 24, 1050 m asl, 14°36′14″N, 108°18′22″E, water temp. 20.5°C, 6 March 2001, CL 4281, coll. J.T. Polhemus & P. Nguyen (USNM, BPBM); 4 males, 6 females (apt), 1 male, 3 females (mpt), stream in dry forest hills 29 km NE. of Kontum on Hwy. 24, 565 m asl, 14°27′01″N, 108°09′12″E, water temp. 20.5°C, 19 March 2001, CL 4284, coll. D.A. Polhemus, J.T. Polhemus & P. Nguyen (USNM); 1 female (apt), 1–4 m trib. of Ngoc Mi River, ca. 20 km NE. of Ngoc Linh, 980 m asl, 10 Sept. 1998, coll. B. Hubley, D.C. Currie & M. Tseng, ROM 982314, secondary tropical forest, 15°08′23″N, 107°54′40″E (USNM). Gia Lai Prov.: 1 male, 3 females (mpt), 40 km NW. An Khe, Buon Luoi, 14°10′N 108°30′E, 620–750 m asl, coll. Pacholátko & Dembicky, 28 March–12 April 1995 (NHMW); 5 males, 1 female (apt), 1 female (mpt), Nuoc Stream, 47 km N. of An Khe, 580 m asl, 14°14′17″N, 108°36′17″E, water temp. 24°C, 23 March 2001, CL 4312, coll. D.A. Polhemus, J.T. Polhemus & P. Nguyen (USNM, BPBM). Binh Dinh Prov.: 7 males, 8 females (apt), 1 female (mpt), rocky stream on E. side of An Khe Pass, 19 km E. of An Khe on Hwy. 19, 115– 200 m asl, 13°58′50″N, 108°47′14″E, water temp. 24°C, 12 March 2001, CL 4291, coll. J.T. Polhemus & P. Nguyen (USNM); 1 male, 3 females (apt), waterfall on E. side of An Khe Pass, 19 km E. of An Khe on Hwy. 19, 170 m asl, 13°58′23″N, 108°46′48″E, water temp. 24°C, 12 March 2001, CL 4292, coll. J.T. Polhemus & P. Nguyen (USNM, BPBM). Phu Yen Prov.: 1 male (apt), stream in granite hills on N. side of Ca Pass, 29 km S. of Tuy Hoa on Hwy. 1, 60 m asl, 12°53′05″N, 109°23′38″E, water temp. 24°C, 25 March 2001, CL 4316, coll. D.A. Polhemus, J.T. Polhemus & P. Nguyen (USNM). Lam Dong Prov.: 1 male (apt), Di Linh, 18 km S. of Bao Loc, 600 m asl, coll. Vásárhelyi, 14 October 1988, No. 283 (MTMB). Dong Nai Prov.: 2 males 1 female (apt), Vinh Cuu, Vinh An, Suoi Rang waterfall, coll. Tran A.D., 10 May 2003, TAD0315b (ZRC). Kien Giang Prov., Phu Quoc Island: 1 male (apt), 1 male (mpt), Da Ban stream & waterfall, coll. Tran A.D. & D. Yeo, 29 November 2010, TAD1020 (ZMHU); 2 males, 1 female (apt), 3 males, 3 females (mpt), Tranh stream (middle section & waterfall), coll. Tran A.D., 30 November 2010, TAD1022 (ZMHU). LAOS: Khammouan Prov.: 3 males, 1 female (apt), 1 male, 1 female (mpt), Ban Khoun Ngeun env., N18°07′E104°29′, alt. 250 m asl, coll. E. Jendek & P. Patcholátko, 4–16, 25–30 November 2000 (NHMW). Saravan Prov.: 1 male, 1 female (apt), Tat Lo Waterfall & Resort, 370 m asl, coll. Schwendinger, 29 December 1996 (NHMW). Vientiane Prov.: 1 male, 6 females (apt), Ban Van Heue, ~ 20 km E. of Phou Khao Khouay park HQ, 1039 m asl, vic. 18°17′44″N, 102°53′48″E, 31 August 1967, coll. J.L. Gressit et al. (BPBM). Luang Prabang Prov.: 2 females (apt), 2 males, 5 females (mpt), Huay La stream, (trib. to Nam Xeuang river), NE. of Ban Pha on road to Pak Xeng, 305 m asl, 20°03′38″N, 102°19′45″E, water temp. 26°C, 6 December 2015, 1000–1200 hrs., CL 6026, coll. D.A. Polhemus (BPBM); 5 males, 5 females (apt), 1 male, 2 females (mpt), Huay Sokor stream, (trib. to Nam Xeuang river), NE. of Ban Pha on road to Pak Xeng, 350 m asl, 20°03′11″N, 102°21′43″E, water temp. 25°C, 6 December 2015, 1330–1500 hrs., CL 6027, coll. D.A. Polhemus (BPBM); 1 male (apt), Nam Bor River, 1.3 km SW. of Ban Phuong Pao village, 365 m asl [1200 ft], 19°57′02″N, 102°28′33″E, water temp. 21°C, 7 December 2015, 0930–1015 hrs., CL 6028, coll. D.A. Polhemus (BPBM); 1 female (apt), 1 male, 1 female (mpt), small forest tributary to Nam Bor River, 1.4 km SW. of Ban Phuong Pao village, 395 m asl, 19°56′59″N, 102°28′29″E, water temp. 21°C, 7 December 2015, 1030–1100 hrs., CL 6029, coll. D.A. Polhemus (BPBM); 3 males, 2 females (apt), 4 males, 1 female (mpt), rocky stream and small clear tributary at Ban Kokvane village, upstream of bridge, 320 m asl [1050 ft], 19°57′07″N, 102°17′36″E, water temp. 23.5°C, 7 December 2015, 1315–1415 hrs., CL 6031, coll. D.A. Polhemus (BPBM); 2 males, 2 females (apt), 1 male (mpt), rocky stream at Tad Thang waterfall area,, 7 km S. of Luang Prabang, 410–440 m asl [1350–1450 ft], 19°50′15″N, 102°07′53″E, water temp. 21°C, 8 December 2015, 0900– 1045 hrs., CL 6032, coll. D.A. Polhemus (BPBM). CAMBODIA: Koh Kong Prov.: 4 males, 1 female (apt), 2 females (mpt), Cardamom Mountains, shaded forest streamlet on road to Tatai Dam overlook, 420 m asl, 11°36′02″N, 103°13′02″E, water temp. 26°C, 30 August 2015, CL 6016, coll. D.A. Polhemus (BPBM, USNM); 3 males, 1 female (mpt), Cardamom Mountains, cascading stream in sandstone bed on road to Tatai Dam overlook, 420 m asl, 11°35′47″N, 103°14′48″E, water temp. 26°C, 30 August 2015, CL 6017, coll. D.A. Polhemus (BPBM, USNM); 2 males, 2 female (apt), Cardamom Mountains, Toeuk Noeng River, 165 m asl, 11°37′33″N, 103°28′51″E, water temp. 26°C, 31 August 2015, CL 6019, coll. D.A. Polhemus (BPBM, USNM); 1 male, 4 female (apt), Cardamom Mountains, outflow from ponded stream on road from Koh Kong to Pursat, 540 m asl, 12°00′58″N, 103°10′47″E, water temp. 24.5°C, 1 September 2015, CL 6023, coll. D.A. Polhemus (BPBM, USNM). THAILAND: Chiang Mai Prov.: 1 male (mpt), N. Thailand, 78 km from Chiang Mai, coll. Y.Y. Goh, 12 June 1998, GYY079 (ZRC); 3 males, 4 females (apt), 1 male, 1 female (mpt), NW. Chiang Mai, stream off Pai River, coll. C.M. Yang & T.B. Lim, 08 September 1998, YCM207 (ZRC); 2 males, 2 females (apt), 1 male, 1 female (mpt), W. Mae Rim, Mae Sa N’Park, Mae Sa Falls, coll. H. Zettel (2), 30–31 October 1995 (NHMW). Kamphaeng Phet Prov.: 1 male (mpt), central Thailand, Kamphaeng Phet, side stream to waterfall, coll. C.M. Yang & T.B. Lim, 12 September 1998, YCM223 (ZRC); 1 female (apt), central Thailand, rocky stream, coll. C.M. Yang & T.B. Lim, 12 September 1998, YCM222A (ZRC). Diagnosis. Male: fore femur incrassate (ratio length/width variable, about 3.63–4.61), ventral surface indented subapically, with pointed proximal edge and a large sub-apical tooth, inner surface of fore tibia with broad indentation basally (not obvious in males with more slender fore femur) (Fig. 77). Male genitalia moderate in size: pygophore sub-ovate; proctiger elongate; paramere falciform, apex blunt (Fig. 38); endosoma as in Chen & Nieser (1993: Fig. 105). Female: inner surface of hind trochanter with long hairs (Fig. 78); sternum 7 large, constricted laterally, posteriorly produced median lobe with parallel lateral margins and round posterior margin, sometimes directed dorsad, completely enclosing genitalia (Fig. 79). Size: apterous males: length 4.31–4.95, width 2.11–2.51; apterous females: length 4.02–4.75, width 2.23–2.52. Remarks. See Remarks for M. acutus. Distribution. Vietnam: Thanh Hoa, Quang Binh, Da Nang, Kon Tum, Gia Lai, Binh Dinh, Phu Yen, Lam Dong, Dong Nai, Phu Quoc (Fig. 139). Extralimital records: Myanmar: Hpungan Sadon, Thailand (northern), Laos (first record), Cambodia (first record).

Published as part of A. D., Tran & Polhemus, D. A., 2017, The genus Metrocoris Mayr, 1865 (Gerromorpha: Gerridae) in Vietnam, with descriptions of five new species, pp. 109-149 in Raffles Bulletin of Zoology 65 on pages 127-128, DOI: 10.5281/zenodo.4502634