Abstract
The preimaginal stages of Tropisternus (Pleurhomus) sahlbergi (Sharp, 1883) are described for the first time, including illustrations and photographs of the egg case, all larval instars and pupa. The descriptions emphasize on the morphometry and chaetotaxy, following current standards in larval descriptions within Hydrophilidae. Preliminary evidence is presented for a placement of Pleurhomus Sharp, 1833 within Tropisternus Solier, 1834, in agreement with a recent phylogenetic analysis based on adultcharacters Tropisternus (P.) sahlbergi is characterized by a brovm to dark brown head capsule without color pattem, mandibles with strongly serrated irmer margins, a short seta PA 11 in comparison to PAH, the absence of seta AN8, the absence of a distalsecondary seta on the outer margin of the first maxillary palpomere and the dorsal surface of the mentum almost entirely covered by spinulae.
NSTL