Revision of the genus Eotrechus Kirkaldy (Hemiptera, Heteroptera, Gerridae), with descriptions of six new species Author Tran, Anh Duc https://orcid.org/0000-0001-9605-0739 Faculty of Biology, University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam tran.anhduc@hus.edu.vn Author Zettel, Herbert https://orcid.org/0000-0002-7760-0472 Herbert Zettel, 2 nd Zoological Department (Entomology), Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria Author Sites, Robert W. https://orcid.org/0000-0002-3895-813X Enns Entomology Museum, University of Missouri, Columbia, MO 65211, USA text Deutsche Entomologische Zeitschrift 2023 2023-03-16 70 1 69 111 http://dx.doi.org/10.3897/dez.70.97117 journal article http://dx.doi.org/10.3897/dez.70.97117 1860-1324-1-69 99BBA4C8ED2048879952B61CC25309D4 CA0CBE818BFA5DFA80DBD42521D5DBE3 Eotrechus petraeus Andersen, 1982 Figs 6 , 7 , 26 Eotrechus petraeus Andersen, 1982: 15-16, figs 10, 18, 20, 24 (type locality: Doi Suthep, Chiang Mai, Thailand). Eotrechus petraeus : Andersen (1998 : 6) (checklist). Material examined. Holotype : Thailand • ♂ (apterous); Chiang Mai Province , Doi Suthep National Park , Mahidol waterfall; 1250 m a.s.l. ; 27 Sep. 1981 ; Zool. Museum Copenhagen leg.; ZMUC. Diagnosis. Size: apterous male: length 7.8, width 2.0 (Andersen, 1982). Male: mesosternum ca. 3.6 x length of metasternum; fore femur incrassate, with a large basal tubercle bearing a round spot of black, minute setae, along flexor side of femur with a row of eight long, stiff setae (three on base, five on elongate part); fore tibia distally thicker and curved, flexor side clearly bisinuate, with scattered stiff setae on exterior side (Fig. 6 ); abdominal sterna II-VI weakly grooved in the middle; sternum VII broadly depressed, slightly shorter than two preceding sterna combined, posterior margin with a large U-shaped median notch about as deep as two-fifths of sternum VII length. Male genitalia: abdominal segment VIII large, ventral side distinctly longer than sternum VII, posterior margin with dense, brownish setae; pygophore with small lateral tubercles bearing a tuft of yellowish setae, which is directed dorsad, caudal projection of pygophore long, triangular, and with apical part evenly curved dorsad (Fig. 7A-D ); paramere elongated, tapering towards apex, length more than twice as width (Fig. 7D ); proctiger with lateral processes rectangular, bearing long, brownish setae, ventral surface with a patch of dark, long, brush-like setae (Fig. 7E, F ). Female unknown. Figure 6. Eotrechus petraeus , habitus of holotype. A. Lateral view; B. Dorsal view (both of same scale). Figure 7. Eotrechus petraeus , holotype. A, B. Genitalia, ventral and lateral views; C, D. Pygophore, lateral and dorsal views; E, F. Proctiger, lateral and dorsal views. ( A, B. Same scale; C-F. Same scale). Remarks. See comparative notes for E. kerberos sp. nov. Some specimens collected at Doi Inthanon (Chiang Mai, Thailand) were recorded as Eotrechus petraeus by Vitheepradit and Sites (2007) ; in fact, they belong to a new species, E. thai sp. nov., as described in a later section of the present paper. Distribution. Thailand: Chiang Mai ( Andersen 1982 ) (Fig. 26 ).