order
                        
                      
                                    Coleoptera
                                       “Adult Beetles”
                                  
                                    Coleoptera
                                       “Larval Beetles”
                                  
                                    Diptera
                                       “True Flies”
                                  
                                    Ephemeroptera
                                       “Mayflies”
                                  
                                    Hemiptera
                                       “True Bugs”
                                  
                                    Lepidoptera
                                       “Aquatic Caterpillars, Snout Moths”
                                  
                                    Megaloptera
                                       “Alderflies, Dobsonflies, and Fishflies”
                                  
                                    Odonata
                                       “Dragonflies and Damselflies”
                                  
                                    Plecoptera
                                       “Stoneflies”
                                  
                                    Trichoptera
                                       “Caddisflies”
                                 family
                        
                     Hydrophilidae
               
            genus
                        
                     Tropisternus
            
                  “Water Scavenger Beetle Larvae”
               
      Genus Overview
                  
               
                        The North American fauna includes at least 14 species of this widespread genus. Larvae are predators climbing among rooted plants in lentic habitats and slow-flowing streams.
                  
               Characteristics
                  
               POLLUTION TOLERANCE
                        Southeast: 9.8 and higher
                                 Mid-Atlantic: 10 and higher
                              0 = least tolerant, 10 = most tolerant
                        FEEDING HABITS
                        
                                 Engulfer / Predator
                        
                     MOVEMENT
                        
                                 Climber
                        
                     DISTRIBUTION
                        
                                 Widespread (east of the Rocky Mtns.)
                        
                     HABITAT
                        
                                 Lentic-littoral
Lotic-depositional
                        
                     Lotic-depositional
Diagnostic Characters
               order
                         
                                       
                                       
                                    Eye Spots
                                  
                                       
                                       
                                    Lateral Gills USUALLY Absent
                                  
                                       
                                       
                                    USUALLY 4-5-Segmented Legs
                                 
                  + Expanded Character List
                  
                     
               
            
                        Order:
                           Larvae: Usually without lateral abdominal gills. If gills present, then 4 hooks clustered on segment 10. Thoracic legs each usually with 4 or 5 segments and with 1 or 2 claws; if without legs, head distinctly sclerotized and posterior body (thorax and abdomen) simple, without gills, hair brushes, suckers, or breathing tube. Eye spots usually present, but compound eyes absent.
                     
                     
                        Family:
                           Each mandible with 1 to 3 teeth along inner margin. Labrum and clypeus not separated by distinct suture. Antennae each 2- or 3-segmented. Head with simple-eyes in groups of 5. Legs each 3- or 4-segmented, with single claw; legs adapted for walking, sometimes small. Thoracic tergites clearly defined. Abdominal tergites without dorsal lobes. Abdomen usually 8-segmented. Body roughly cylindrical or spindle-shaped, not markedly thick. Head and legs visible in dorsal view.
                     
                     
                        Genus:
                           Head subquadrangular or subrectangular; frontal sulci V-shaped. Antennae further than mandibles from anterolateral angles of head; uniramal, without finger-like antennal appendage. Apex of ligula not bifid. Pronotum entirely sclerotized. Mentum with sides almost straight, its anterolateral angles very prominent. Mesonotal and metanotal sclerites much reduced, triangular. Femora each with fringe of long swimming hairs. Eight complete abdominal segments, with segments IX and X reduced and forming stigmatic atrium or cavity. One pair of rudimentary, tubercular, lateral gills on each abdominal segment, each with several terminal setae, those of segment IX short.
                     
                   
                   
            Dorsal
               Ventral
               


