Regimbartia Zaitzev, 1908

Minoshima, Yûsuke N. & Hayashi, Masakazu, 2015, Description of the larval stages of the berosine genera Berosus and Regimbartia based on the Japanese species B. japonicus and R. attenuata (Coleoptera: Hydrophilidae), Acta Entomologica Musei Nationalis Pragae 55 (1), pp. 47-83 : 61-62

Genus Regimbartia Zaitzev, 1908

( Figs 8–16 , 17C–D )

Diagnosis. The larva of Regimbartia is very similar to those of genera Allocotocerus and Derallus . Larvae of these genera are distinguishable from other hydrophilid larvae by the following combination of characters: (1) almost symmetrical clypeolabrum ( Figs 9C , 13C ); (2) the presence of an inner projection on antennomere 1 (autapomorphy of Berosini ; Figs 10A–B , 15A–B ), (3) almost symmetrical to slightly asymmetrical mandibles ( Figs 11A–B ); (4) elongated prementum ( Figs 11C–D , 15C–D ); and (5) presence of short to long setiferous abdominal projections on the dorsal to lateral surface (e.g., Fig. 8D ). Regimbartia is distinguishable from Allocotocerus and Derallus by antennal characters: apex of inner projection on antennomere 1 rounded; antennomere 2 widened distally, without inner extension apically.

Within the Japanese aquatic Hydrophilidae , the larva may superficially resemble those of Amphiops Erichson, 1843 , Hydrochara , and Sternolophus Solier, 1834 in the head morphology: i.e., elongate antennae, mandibles, and maxilla (e.g., MINOSHIMA & HAYASHI 2011a, 2012; MINOSHIMA et al. 2012; WATTS 2002); however Regimbartia is easily distinguishable from them by the aforementioned characters. See also a key to the genera of Japanese aquatic Hydrophilidae in MINOSHIMA & HAYASHI (2011a).

Figures

Fig. 8. Third instar larva of Regimbartia attenuata (Fabricius, 1801). A–B – habitus, dorsal (A) and ventral (B); C – cuticular projection on pronotum, dorsal; D – lateral setiferous projection, dorsal; E – cuticular projections on abdominal segment, dorsal.

Fig. 9. First instar larva of Regimbartia attenuata (Fabricius, 1801), head capsule. A–B – head capsule, dorsal (A) and ventral (B); C – anterior margin of head capsule, dorsal; D–E – variation of sensilla PA15–18, ventral.

Fig. 10. First instar larva of Regimbartia attenuata (Fabricius, 1801), head appendages. A–B – antenna, dorsal (A) and ventral (B); C–D – maxilla, dorsal (C) and ventral (D).

Fig. 11. First instar larva of Regimbartia attenuata (Fabricius, 1801), head appendages. A–B – mandible, dorsal; C–D – labium, dorsal (C) and ventral (D).

Fig. 12. Third instar larva of Regimbartia attenuata (Fabricius, 1801). A – head, dorsal; B – prosternal sclerite, ventral; C – spiracular atrium, dorsal.

Fig. 13. Third instar larva of Regimbartia attenuata (Fabricius, 1801), head capsule.A–B – head capsule, dorsal (A) and ventral (B); C – anterior margin of head capsule, dorsal.

Fig. 14. Third instar larva of Regimbartia attenuata (Fabricius, 1801), head appendages. A–B – antenna, dorsal (A) and ventral (B); C–D – maxilla, dorsal (C) and ventral (D).

Fig. 15. Third instar larva of Regimbartia attenuata (Fabricius, 1801), head appendages. A–B – mandible, dorsal; C–D – labium, dorsal (C) and ventral (D).

Fig. 16. Regimbartia attenuata (Fabricius, 1801), mesothoracic leg, anterior view. First (A) and third (B) instar.

Fig. 17. A–B – Egg-case of Berosus (Berosus) japonicus Sharp, 1873, wild (A) and rearing (B); C – egg-case of Regimbartia attenuata (Fabricius, 1801), rearing; D – egg of R. attenuata. FigsA, C modified after HAYASHI (2009a). Photos by M. Hayashi.