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
                        
                     Dytiscidae
               
            
                  “Predacious Diving Beetles”
               
      Genus Overview
                  
               
                        There are at least 106 species of this genus in North America. Adults and larvae inhabit both fast and slow streams and littoral zones of lentic habitats. They are piercing predators. Adults are climbers on rooted plants and efficient swimmers.
                  
               Characteristics
                  
               POLLUTION TOLERANCE
                        Mid-Atlantic: 8 and higher
                              0 = least tolerant, 10 = most tolerant
                        FEEDING HABITS
                        
                                 Piercer / Predator
                        
                     MOVEMENT
                        
                                 Diver
Swimmer
                        
                     Swimmer
DISTRIBUTION
                        
                                 Widespread (east of the Rocky Mtns.)
                        
                     HABITAT
                        
                                 Lentic-littoral
Lotic-depositional
Lotic-erosional
                        
                     Lotic-depositional
Lotic-erosional
Diagnostic Characters
               order
                         
                                       
                                       
                                    Elytra
                                 family
                         
                                       
                                       
                                    Coxal Plate Not Wedge-like
                                  
                                       
                                       
                                    Extended Hind Coxae
                                  
                                       
                                       
                                    Large Spurs Absent
                                  
                                       
                                       
                                    Scutellum Usually Visible
                                 
                  + Expanded Character List
                  
                     
               
            
                        Order:
                           Adults with hardened forewings (elytra) covering the hind wings. 
                     
                     
                        Family:
                           Ventrally, pronotum with conspicuous curved lines near each lateral margin (notopleural sutures). Metasternum without transverse sutures. Elytra covering entire abdomen or exposing only part of 1 tergite. Hind coxae each with median portion extending in posterior direction, dividing abdominal segment 1 into lateral sclerites, but not expanding into broad plates. Without large spur on end of each front tibia. Dyticidae without broad wedge-like hind coxal plate. Scutellum usually visible; if hidden, then front and middle tarsi apparently 4-segmented and hind tarsi each with 1 claw. Hind tarsi and usually tibiae flattened, streamlined, and bearing long, stiff swimming bristles. Body usually 3–25 mm long.
                     
                     
                        Genus:
                           Moderate-sized, 5 to 14 mm long, and black or brown, with elytra appearing leathery with small cracks or net-like. Pronotum margined. Males with tarsi of front legs swollen and bearing dense setae tipped with minute discs. Hind claws of equal length. Metacoxal lines not strongly convergent anterior of metacoxal lobes; elytra without longitudinal striae; metafemora with or without setae on posteroapical angles.
                     
                   
                   
            Dorsal
               Ventral
               


