Larvae of four species of the Hyphydrus lyratus species-group (Coleoptera: Dytiscidae: Hydroporinae)

Abstract  The third instars of the Australian species Hyphydrus lyratus Swartz, H. contiguus Wehncke, H. elegans (Montrouzier) and H. decemmaculatus Wehncke (Coleoptera: Adephaga: Dytiscidae) are described, including a chaetotaxic analysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. Larvae of these species morphologically resemble other species of Hyphydrus Illiger for which the larvae have been described. A key to identify larvae of the Australian species of Hyphydrus is provided. Larvae of H. effeminatus Watts appear identical to those of H. decemmaculatus . A 822 bp fragment of the CO1 gene of larvae and adults of these species showed very slight differences, suggesting the possibility that, in Australia at least, H. decemmaculatus is polymorphic.