Hydrometridae, Polhemus, 2022

Polhemus, Dan A., 2022, Two new genera and six new species of Terrestrial Hydrometridae (Hemiptera: Heteroptera) from French Polynesia, Zootaxa 5190 (1), pp. 69-98 : 71

Key to the genera of Hydrometridae occurring in French Polynesia

1. Head extremely elongate, length subequal to that of thorax and abdomen combined ( Figs. 30–32 ); Marquesas Islands (Ua Huka).............................................................................. Dolichocephalometra

- Head not as elongate as above, length two-thirds or less the length of the thorax and abdomen combined ( Figs. 1 , 2 , 10 , 11 , 12 , 37 )................................................................................................. 2

2. Legs bearing numerous long, erect setae, the lengths of these setae exceeding the widths of the segments on which they occur ( Figs. 35, 36 ); head relatively short, less than half the length of the thorax and abdomen combined ( Fig. 37 ); Marquesas Islands (Hiva Oa).................................................................................. Chaetometra

- Legs lacking numerous long, erect setae, although such setae may be present on the body ( Prohydrometra englundi n. sp.); length of head over half the length of the thorax and abdomen combined ( Fig. 1 ); Society or Marquesas Islands .......... 3

3. Antennomere III very long, over 5 times the length of antennomere II ( Fig. 11 ); fore-to-middle coxal spacing distinctly less than middle-to-hind coxal spacing, ratio 1.00/1.45 ( Fig. 9 ); male abdominal sternum VII modified, bearing paired processes or patches of bristle-like setae ( Figs. 19–24 ); Society Islands (Moorea, Raiatea, Tahiti)............... Prohydrometra n. gen.

- Antennomere III much shorter than above, slightly over 3 times as long as antennomere II ( Fig. 1 ); fore-to-middle versus middle-to-hind coxal spacing subequal, ratio 1.00/1.20 ( Fig. 3 ); male abdominal sternum VII unmodified, lacking paired processes or patches of bristle-like setae ( Fig. 4 ); Marquesas Islands (Hiva Oa).................. Marquesametra n. gen.

Figures

FIGURE 1. Marquesametra hivaoa n. sp., dorsal habitus. Specimen from Marquesas Islands, Hiva Oa, Mt. Temetiu, CL 6031. Young Sohn illustration.

FIGURE 11. Prohydrometra johnpolhemi n. sp., head in lateral view, showing very long antennal segment III diagnostic for this genus. Specimen from French Polynesia, Raiatea, Trois Cascade, CL 7521.

FIGURES 30–32. Dolichocephalometra pacifica, holotype, structural details. 30. Lateral view. 31. Dorsal view. 32. Head.

FIGURES 2–4. Marquesametra hivaoa n. sp., morphological details. 2. Male head, dorsal view, with positions of trichobothria indicated. 3. Male ventral right thorax, showing nearly equidistant coxal spacing. 4. Male ventral terminal abdomen. Specimen from French Polynesia, Hiva Oa, Mt. Temetiu, CL 6031.

FIGURES 9, 10. Prohydrometra gagnei, morphological details. 9. Male ventral left thorax, showing coxal spacing. 10. Male head, dorsal view, with positions of cephalic trichobothria indicated. Specimen from French Polynesia, Tahiti, Mt. Marau, CL 7498.

FIGURES 12–15. Prohydrometra englundi n. sp., female, morphological details. 12. Head, dorsal view, with positions of cephalic trichobothria indicated. 13. Ventral left thorax, showing coxal spacing. 14. Terminal abdomen, ventral view. 15. Left foreleg, ventral view. Specimen from French Polynesia, Raiatea, Mt. Toomaru.

FIGURES 35–37. Chaetometra robusta, holotype, structural details. 35. Lateral view. 36. Dorsal view. 37. Head.

FIGURES 19–24. Prohydrometra n. gen. species, male ventral terminal abdomen. 19. P. gagnei, specimen from Tahiti, Mt. Marau. 20. P. gagnei, specimen from Tahiti, Mt. Mauru, showing yellowish-brown coloration. 21. P. moorea n. sp., specimen from Moorea, Mt. Tohiea. 22. P. teatara n. sp., specimen from Tahiti, Mts. Teatara. 23. P. tohiea n. sp., holotype, specimen from Moorea, Mt. Tohiea. 24. P. johnpolhemi n. sp., specimen from Raiatea, Trois Cascade.