The genus Metrocoris Mayr, 1865 (Gerromorpha: Gerridae) in Vietnam, with descriptions of five new species Author A. D., Tran Author Polhemus, D. A. text Raffles Bulletin of Zoology 2017 2017-05-24 65 109 149 journal article 6572 10.5281/zenodo.4502634 fde5f083-514d-400b-b886-e792390afd86 2345-7600 4502634 E9197A2F-EE46-4E5E-93C5-37E4CEC1A240 Metrocoris vietnamensis Tran & Zettel, 2005 ( Figs. 9 , 52–55 ) Metrocoris vietnamensis Tran & Zettel, 2005: 42–45 , Figs. 1–9 , 24, 26, 27 ( type locality: Ba Na - Nui Chua , Da Nang , Vietnam ). Material examined. Holotype and paratypes : see Tran & Zettel (2005) . Others : VIETNAM : Da Nang Prov. : 1 male , 1 female (apt), Ba Na - Nui Chua , Suoi Nai - Thac Cau Vong , coll. Tran A.D. & Tan H.H. , 01 March 2005 , THH05-23 ( ZRC ); 3 males , 5 females (apt), Ba Na - Nui Chua , Suoi Vong Nguyet , coll. Tran A.D. & Tan H.H. , 01 March 2005 , THH05-24 ( ZRC ) . Diagnosis. Male: fore femur variably incrassate (ratio length/width: 3.03–4.36), ventral surface of fore femur in distal one-fourth with black indentation which proximally marked by distinct tooth, and with single stout sub-apical tooth; inner surface of fore tibia subbasally with tooth-like elevation (indistinct in males with small fore leg) ( Figs. 52, 53 ). Male genitalia: pygophore not raised posteriorly, caudal margin broadly rounded, caudal face with paired, shallow impressions, dorso-lateral process curved and apically blunt (see Tran & Zettel, 2005 : Figs. 4, 5 ); proctiger elongate (see Tran & Zettel, 2005 : Fig. 5 ); paramere prominent, falciform, strongly curved and apically strongly narrowed ( Fig. 54 ); endosoma: dorsal sclerite long and recurved proximally, apical accessory sclerite distinct, lateral sclerite very large, slightly curved, ventral sclerite short, thin accessory lateral sclerite present (see Tran & Zettel, 2005 : Figs. 7, 8 ). Sternum 7 of female ( Fig. 55 ): large, slightly longer than preceding abdominal sterna together, posterior one-third constricted, bifid forming two widely separated lobes, slightly slanting but not curved dorsad; notch between lobes as wide as each lobe; apices of lobes pointed, reaching apex of abdomen in ventral view. Size: apterous males: length 6.0–6.8 ( holotype 6.7), width 2.67–3.06 ( holotype 2.96), macropterous males: length 6.2, width 2.73; apterous females: length 5.1–5.5 ( allotype 5.4), width 2.81–3.10 ( allotype 3.01). Remarks. Metrocoris vietnamensis belongs to the Metrocoris bilobatus species group (sensu Chen & Nieser, 1993 ), and is the second species of this group found in Vietnam , the first being M. bilobatoides (see Chen & Nieser, 1993 ). A detailed comparison of Metrocoris vietnamensis with its congeners in the M. bilobatus group has already been provided by Tran & Zettel (2005: 44–45) . For further comparisons with other members of M. bilobatus group which occur in Vietnam , see subsequent Remarks under M. johnpolhemi , new species . Distribution. Vietnam : Da Nang ( Fig. 138 ).