Hydrotrephes, China, 1935

Zettel, Herbert, ek, Miroslav Papá & Kovac, Damir, 2011, Guide To The Aquatic Heteroptera Of Singapore And Peninsular Malaysia: Vii. Family Helotrephidae, Raffles Bulletin of Zoology 59 (2), pp. 171-179 : 178

Key to the species of Hydrotrephes

1 Metasternal carina long, with straight ventral margin; abdominal sternite 4 with small medial tubercle ( Fig. 22 ). Aedeagus simple ( Figs. 64 ). Southern Thailand. Hydrotrephes mirus group ...... ............................................................. [ Hydrotrephes mixtus ]

– Metasternal carina short, with convex ventral margin; abdominal sternite 4 without medial tubercle (e.g., Fig. 23 ). Aedeagus modified, posteriorly or postero-subapically with process or tooth ( Figs. 65, 68, 71, 74 ) .................................................. 2

2 Subgenital plate of female with triangular apical lamella ( Figs. 60, 61 ). Hind margin of aedeagus with long process ( Figs. 65, 68 ). Right paramere stout, with broad apex ( Figs. 67, 70 ). Hydrotrephes bouvieri group ............................................... 3

– Subgenital plate of female distally either with broad lobe or with long and slender process ( Figs. 62, 63 ). Hind margin of aedeagus with short tooth ( Figs. 71, 74 ). Right paramere slender, with pointed apex ( Figs. 73, 76 ). Hydrotrephes martini group ............................................................................................... 4

3 Subgenital plate of female with small distal lamina ( Fig. 60 ) Aedeagus with triangular apex and curved posterior process ( Fig. 65 ). Southern Thailand................ [ Hydrotrephes sitesi ]

– Subgenital plate of female with large distal lamina ( Fig. 61 ). Aedeagus with elongate apex and straight posterior process ( Fig. 68 ). Southern Thailand........ [ Hydrotrephes maculatus ]

4 Body length 1.9–2.2 mm, cephalonotum width 1.3–1.5 mm. Subgenital plate of female distally with broad lobe ( Fig. 63 ). Aedeagus with roundish apex ( Fig. 71 ) ................................... .................................................... Hydrotrephes langkawicus

– Body length 2.6–2.8 mm, cephalonotum width 1.8–2.1 mm. Subgenital plate of female distally with long and slender process ( Fig. 62 ). Aedeagus with elongate apex ( Fig. 74 ). ...................................................... Hydrotrephes benomensis

Figures

Figs. 12–24. Key characters of helotrephid genera. 12–14, Hemielytron in situ, dorsolateral aspect; cla = clavus, cls = claval suture, emb = embolium, pse = pseudendocorium, psm = pseudomembrane. (12) Platytrephes sitesi, hindwing-brachypterous morph, (13) Helotrephes australis, hindwing-brachypterous morph, and (14) Helotrephes australis, macropterous morph. 15–19, Cephalonotum (pnp = pronotal plate), lateral aspect, of (15) Helotrephes australis, (16) Distotrephes zetteli, hindwing-brachypterous morph, (17) Distotrephes pavelstysi Zettel, 1999, macropterous morph, (18) Tiphotrephes indicus, (19) Idiotrephes chinai. 20–23, Ventromedial carinae of thoracic and abdominal sternites, lateral aspect; prs – prosternum, mss – mesosternum, mts – metasternum, 2, 3, 4 etc. abdominal sternites 2, 3, 4 etc. (20) Helotrephes australis, (21) Ascetotrephes edmundsorum, (22) Hydrotrephes mixtus, (23) Hydrotrephes belomensis. 24, Metasternal carinae in Distotrephes zetteli, ventral aspect. Images not to scale.

Figs. 40–76. Key characters of species of Helotrephini. (40, 41) Pronotal plate (pnp) and genal plate (gp), ventrolateral aspect, (44–47, 60–63) Subgenital plate of female, ventral aspect, pilosity omitted in Figs. 44, 60–63) male genitalia in lateral (left) aspect: (48, 51, 54, 57, 64, 65, 68, 71, 74) aedeagus of male, (49, 52, 55, 58, 66, 69, 72, 75) left paramere of male, (50, 53, 56, 59, 67, 70, 73, 76) right paramere of male. 42, 44, 48 – 50, Helotrephes australis, 45, 51–53, Helotrephes affinis, 43, 46, 54–56, Helotrephes flaviceps, 47, 57–59, Helotrephes rompinensis, 60, 65–67, Hydrotrephes sitesi, 61, 68–70, Hydrotrephes maculatus (redrawn from Papá ek & Kovac, 2001a; slightly modified), 62, 74–76, Hydrotrephes benomensis, 63, 71–73, Hydrotrephes langkawicus, 64, Hydrotrephes mixtus.