Larval morphology of Crephelochares and Peltochares (Coleoptera: Hydrophilidae)

Abstract: The larval morphology of Crephelochares Kuwert, 1890 and Peltochares Régimbart, 1907 is described in detail based on specimens of C. abnormalis (Sharp, 1890) and P. atropiceus (Régimbart, 1903) collected in Taiwan; the chaetotaxy of the head capsule and head appendages of both genera is described for the first time. Larvae were obtained by laboratory rearing and field collecting; field collected larvae were identified by morphological comparison with those reared in the laboratory. Larval morphology of C. abnormalis corresponds with that of C. nitescens (Fauvel, 1883) except for the serrate margin of the nasale in C. abnormalis. We confirm that Crephelochares does not construct the usual egg case, and report active behaviour of its larvae, possibly indicating they are not ambush predators. Larval morphology of P. atropiceus corresponds with that of P. foveicollis; on the other hand, we conclude that the larvae previously described as Peltochares from Madagascar belong to Tritonus Mulsant, 1844 of the tribe Laccobiini. The egg-carrying behaviour of Peltochares is confirmed. We briefly summarize the state of the knowledge of immature stages of the Acidocerinae, indicating that a special effort in discovering and describing immature stages from northern South America and Brazil is needed.

Key words: Coleoptera, Hydrophilidae, Acidocerinae, aquatic beetles, chaetotaxy, immature stages, Taiwan, Oriental Region