Description of the Second and Third Instars of Laccornellus lugubris (Aubé) (Coleoptera: Dytiscidae: Hydroporinae)

Abstract

The second and third instars of Laccornellus lugubris (Aubé) are described and illustrated for the first time, including detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. Laccornellus Roughley and Wolfe shares with Canthyporus Zimmermann a similar shape and secondary setation of the last abdominal segment, the absence of secondary spine-like setae on the lateral margins of the parietal, and the presence of well-developed spinular pectens on the ventral surface of the femora (this last character also is shared with Laccornis Gozis). On the other hand, larvae of Laccornellus differ from those of Canthyporus, Laccornis, and Hydrovatus Motschulsky in the presence of secondary pores on the ventral surface of the prementum and of secondary setae on the tibia, metatarsus, and anterodorsal surface of femur. The known distributional range of L. lugubris is considerably expanded.