The Hydraenidae (Coleoptera) Of The Republic Of Singapore Author Jäch, Manfred A. Author Díaz, Juan A. Author Skale, Andre text Raffles Bulletin of Zoology 2013 2013-02-28 61 1 53 71 journal article 10.5281/zenodo.5351598 2345-7600 5351598 KEY TO THE SPECIES OF HYDRAENA FROM SINGAPORE 1. Punctures of dorsal surface, especially pronotum and elytra small and shallow, elytal interstices not convex ( Figs. 1, 3, 4 ). Body length: 1.05–1.50 mm ...................................................2 – Punctures of dorsal surface, especially pronotum and elytra, moderately large, dense and well impressed, elytral interstices convex ( Fig. 2 ). Body length: 1.25–1.50 mm ........................4 2. Mesoventral process ( Fig.12 ) wider than mesotibia.Metaventral plaques present or absent. Body length: 1.05–1.50 mm ........3 – Mesoventral process ( Fig. 13 ) not wider than mesotibia. Metaventral plaques absent. Body length: 1.05–1.25 mm ....... ...................................................................... H. singaporensis 3. Middle of pronotum darkened (except for teneral specimens). Metaventral plaques present, distinctly convergent anteriorly ( Fig. 12 ). Male: foretibia slightly curved, not dilated, with subapical denticle on mesal face. Female tergite X and gonocoxite ( Fig. 6e, f ) more transverse, laterally more rounded. Body length: 1.25–1.50 mm ............................... H. hendrichi – Middle of pronotum not darkened. Metaventral plaques absent. Male: foretibia not curved, dilated (lateral view), without denticle. Female tergite X and gonocoxite ( Fig. 7e, f ) less transverse, laterally less rounded, apically subacuminate. Body length: 1.05–1.20 mm ................................................ H . yangae 4. Male: Metaventral plaques thin, carinate ( Fig. 14 ). Aedeagi as in Figs. 8a–c or 9a–c. Female: Abdominal sternite VIII produced apically (see Jäch & Díaz, 1999: Fig. 7d ) or gonocoxite small, subquadrate ( Fig. 9f ).................................5 – Male: Metaventral plaques unmodified. Aedeagi as in Figs. 10a–c or 11a–c. Female: Abdominal sternite VIII apically never produced; gonocoxite transverse, lateral margin distinctly convex subbasally ( Figs. 10e , 11e )........................6 5. Maxillary palpi never darkened subapically. Aedeagus Yshaped ( Fig. 8a–c ). Female: Abdominal sternite VIII produced apically (see Jäch & Díaz, 1999: Fig. 7d ) .. H. michaelbalkei – Maxillary palpi usually slightly darkened subapically. Aedeagus not Y-shaped (see Fig. 9a–c ). Female: Abdominal sternite VIII not produced apically........................ H. formula 6. Male foretibia slightly curved, without denticle. Aedeagus as in Fig. 10a–c , ventral margin of main piece with conspicuous denticle near insertion of left paramere; apex of main piece not wide in ventral view. Female tergite X ( Fig. 10f ) less transverse. Gonocoxite ( Fig. 10e ) more transverse.................. .............................................................................. H. jacobsoni – Male foretibia not curved, provided with very small denticle on mesal face near apical 0.3. Aedeagus as in Fig. 11a–c , ventral margin of main piece without conspicuous denticle; apex of main piece very wide in ventral view. Female tergite X ( Fig. 11f ) more transverse. Gonocoxite ( Fig. 11e ) less transverse ...................................................... H. paulmoritz