Lethocerus Mayr, 1853

Novoselsky, Tanya, Chen, Ping-Ping & Nieser, Nico, 2018, A review of the giant water bugs (Hemiptera: Heteroptera: Nepomorpha: Belostomatidae) of Israel, Israel Journal of Entomology (Oxford, England) 48 (1), pp. 119-141 : 121-122

Genus Lethocerus Mayr ( L. cordofanus Mayr , L. patruelis (Stål))

Identification key to the Belostomatidae species from Israel

1 Segment 1 of rostrum short, thicker than long and shorter than segment 2 ( Figs 2, 4, 14). Abdominal sternites 5 and 6 clearly divided laterally ( Figs 2, 4, 18). Spiracles located on or adjacent to mesal margins of ventral laterotergites ( Fig. 18) (subfamily Lethocerinae ). Foretarsus 3-segmented, with 1 large and strong and 1 reduced claw ( Figs 29, 30). Genital operculum of females with spines and acutely rounded at apex ( Lethocerus )................................................................ 2

– Segment 1 of rostrum longer than thick, subequal in length to segment 2 ( Figs 6, 9, 11, 13, 15–17). Abdominal sternites not clearly divided laterally ( Figs 6, 9, 11, 13, 19–22). Spiracles located near centre of ventral laterotergites ( Figs 19–22) (subfamily Belostomatinae )............................................................................... 3

2 Prosternum medially with keel-bearing beak-like apical attenuation ( Fig. 24). Male genital capsule as in Figs 34, 35. Paramere with bent/curved keel ( Figs 38, 39). Diverticulum flanged/cap­like ( Figs 42–44). Body length, ♀ 65.2–68.1, ♂ 73.0–75.1 mm.................................................................. Lethocerus cordofanus

– Prosternum with ulu-shaped keel ( Fig. 23). Male genital capsule as in Figs 36, 37. Keel on paramere not bent ( Figs 40, 41). Diverticulum not flanged ( Figs 45–47). Body length, ♀ 78.1–83.4, ♂ 63.2–70.1 mm....... Lethocerus patruelis

4 Foretarsus 2­segmented with one claw. Foretibiae and foretarsi laterally flattened ( Figs 28, 31) ( Belostoma or Appasus ) ............................................................... 5

– Foretarsus 3-segmented with two claws ( Figs 32, 33). Foretibiae and foretarsi laterally flattened or cylindrical ( Hydrocyrius or Limnogeton ) ......................... 6

5 Prosternum medially with rounded-triangular projection ( Fig. 25). Membrane of hemelytron developed ( Fig. 10). Forefemur with groove, widest at mid-length, ratio 1:5. Abdominal pilosity as in Figs 11, 19. Female genital operculum bare. Body length, ♀ 25.5±3.2, ♂ 21.1±3.4 mm................... Belostoma bifoveolatum

– Prosternum medially with broadly triangular projection ( Fig. 26). Membrane of hemelytron reduced ( Figs 5–7). Forefemur with projection. Abdominal pilosity of ventral laterotergites 4 not attaining external margin ( Figs 6, 20). Female genital operculum with 2 tufts of setae on apex. Body length, ♀ 17.3±1.5, ♂ 16.3±1.7 mm.............................................................. Appasus urinator urinator

6 Fore tibiae and tarsi laterally flattened, with 2 large unequal claws ( Fig. 32). Forefemur with 2 grooves. Prosternum medially with ulu-shaped keel. Abdominal pilosity as in Figs 13, 21. Female genital operculum with 1 apical tuft of setae. Body, length, ♀ 67.2 mm.................... Hydrocyrius colombiae colombiae

– Foretibiae and foretarsi laterally cylindrical, with 2 short equal claws ( Fig. 33). Forefemur with 1 wide flat groove. Prosternum medially with spine­like projection ( Fig. 27). Abdominal pilosity of ventral laterotergites 4 attaining external margin along its entire length ( Figs 9, 22). Genital operculum of female fringed with hairs. Body length, ♀ 50.0±3.7, ♂ 43.1±3.5 mm ......... Limnogeton fieberi