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
                  
               
                        Larvae and adults occur in slow-moving streams and among rooted plants of lentic habitats; both life stages are piercing predators. Adults are efficient swimmers and divers.
                  
               Characteristics
                  
               POLLUTION TOLERANCE
                        Southeast: 9.1 and higher
                                 Midwest: 5 and higher
                                 Mid-Atlantic: 5 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-depositional
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:
                           Smaller beetles 3.5-5.0 mm long. Elytra with longitudinal striae. Metacoxal lines strongly convergent and almost contacting medial line anterior of metacoxal lobes, then diverging anteriorly. Metafemora lacking groups of setae at posteroapical angles.
                     
                   
            Dorsal
               


