Helochares, Mulsant, 1844

Minoshima, Yûsuke & Hayashi, Masakazu, 2011, Larval morphology of the Japanese species of the tribes Acidocerini, Hydrobiusini and Hydrophilini (Coleoptera: Hydrophilidae), Acta Entomologica Musei Nationalis Pragae (suppl.) 51, pp. 1-118 : 53

Key to the known species of the genus Helochares from Japan (all instars) 2

1. Secondary sensilla between PA6 and PA7 absent ( Fig. 29A ); mandible with two setae (MN1 and MN5) ( Figs. 30 B–C); distal part of outer face of stipes with two setae ( MX 5 and MX 6) ( Figs. 30 D–E); lateral face of mentum without stout setae ( Figs. 30 F–G). First instar. ............................................................................................................................... 2

- Secondary sensilla between PA6 and PA7 present ( Figs. 34 , 43 ); mandible with more than two setae ( Figs. 33 C–D); distal part of outer face of stipes with three setae ( Figs. 33 E–F); lateral face of mentum with stout setae ( Figs. 33 G–H). Second and third instars. ......... 4

2. Epistomal lobe with one short scale-like seta and two short, trichoid to spiniform setae ( Fig. 29C ). ..................................................... H. (Helochares) pallens ( MacLeay, 1825)

- Epistomal lobe with two short scale-like setae and two short, trichoid to spiniform setae ( Fig. 36C ). ....................................................................................................................... 3

3. Seta PA7 trichoid ( Fig. 36A ). ....................... H. (Hydrobaticus) anchoralis Sharp, 1890

- Seta PA7 scale-like ( Fig. 38A ). ............... H. (Hydrobaticus) nipponicus Hebauer, 1995

4. Epistomal lobe with one short scale-like seta and two short, trichoid to spiniform setae ( Fig. 33A ). ..................................................... H. (Helochares) pallens ( MacLeay, 1825)

- Epistomal lobe with two short scale-like setae and two short, trichoid to spiniform setae ( Fig. 42A ). ............................................... H. (Hydrobaticus) nipponicus Hebauer, 1995

Figures

Fig. 29. Head capsule of Helochares (Helochares) pallens (MacLeay, 1825), first instar.A – dorsal view; B – ventral view; C – detail of anterior margin of head capsule, dorsal view.

Fig. 30. Head appendages of Helochares (Helochares) pallens (MacLeay, 1825), first instar. A – antenna, dorsal view; B–C – mandibles, dorsal view; D – maxilla, dorsal view; E – maxilla, ventral view; F – labium, dorsal view; G – labium, ventral view.

Fig. 34. Helochares (Helochares) pallens (MacLeay, 1825), chaetotaxy of head capsule, dorsal view. A – median part of head capsule, second instar. B–D – third instar larva: B – median part of head capsule; C – intraspecific variation of secondary sensilla between PA6 and PA7; D – intraspecific variation of secondary sensilla on outer part of antennal socket. Secondary sensilla are marked by a black rhombus.

Fig. 43.Helochares (Hydrobaticus) nipponicus Hebauer, 1995, chaetotaxy of head capsule, dorsal view.A–B – second instar larva:A – median part of head capsule; B – intraspecific variation of secondary sensilla between PA6 and PA7. C–D – third instar larva: C – median part of head capsule; D – intraspecific variation of secondary sensilla between PA6 and PA7. Secondary sensilla are marked by a black rhombus.

Fig. 33. Helochares (Helochares) pallens (MacLeay, 1825), third instar.A – clypeolabrum, dorsal view; B – antenna, dorsal view; C–D – mandibles, dorsal view; E – maxilla, dorsal view; F – maxilla, ventral view; G – labium, dorsal view; H – labium, ventral view.

Fig. 36. Head capsule of Helochares (Hydrobaticus) anchoralis Sharp, 1890, first instar.A – dorsal view; B – ventral view; C – detail of anterior margin of head capsule, dorsal view.

Fig. 38. Head capsule of Helochares (Hydrobaticus) nipponicus Hebauer, 1995, first instar. A – dorsal view; B – ventral view; C – detail of anterior margin of head capsule, dorsal view.

Fig. 42. Helochares (Hydrobaticus) nipponicus Hebauer, 1995, third instar.A – clypeolabrum, dorsal view; B – antenna, dorsal view; C–D – mandibles, dorsal view; E – maxilla, dorsal view; F – maxilla, ventral view; G – labium, dorsal view; H – labium, ventral view.