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”
                                 genus
                     Nigronia
            
               “Dark Fishflies”
            
      Genus Overview
                  
               
                        The genus Nigronia includes two North American species, N. fasciata and N. serricornis. They are found in lotic-erosional and -depositional habitats, usually in streams with coarse sediments and detritus, often clinging/climbing under or on rocks, especially under bark or in crevices of woody debris. Like other hellgrammites, they are engulfing predators. These species are found throughout eastern and central United States and Canada.
                  
               Characteristics
                  
               POLLUTION TOLERANCE
                        Southeast: up to 5.8
                                 Upper Midwest: up to 0
                                 Midwest: up to 2.7
                              0 = least tolerant, 10 = most tolerant
                        FEEDING HABITS
                        
                                 Engulfer / Predator
                        
                     MOVEMENT
                        
                                 Burrower
Climber
Clinger
                        
                     Climber
Clinger
DISTRIBUTION
                        
                                 Widespread (east of the Rocky Mtns.)
                        
                     HABITAT
                        
                                 Lotic-depositional
Lotic-erosional
                        
                     Lotic-erosional
Diagnostic Characters
               order
                         
                                       
                                       
                                    1 Tail or 2 Prolegs 
                                  
                                       
                                       
                                    Lateral Filaments
                                 family
                         
                                       
                                       
                                    Lateral Filaments
                                  
                                       
                                       
                                    Prolegs With Two Claws
                                 genus
                         
                                       
                                       
                                    Gill Tufts Absent
                                  
                                       
                                       
                                    Short Respiratory Tubes
                                 
                  + Expanded Character List
                  
                     
               
            
                        Order:
                           Larval wings/wing pads absent. Eye spots present, but compound eyes absent. Segmented legs present on thorax. Abdominal segment 9 with either one slender tail or pair of anal prolegs, each with two hooks. Seven or eight pairs of filaments or gills laterally on abdomen, with never more than one pair per segment.
                     
                     
                        Family:
                           Abdominal segments 1–8 with paired, 2-segemented, lateral filaments. Abdominal segment 10 has pair of 1-segemented filaments. End of abdomen with pair of anal prolegs, each bearing 2 claws. Mature larvae 30–65 mm long.
                     
                     
                        Genus:
                           Head without conspicuous color pattern. Abdominal ventral gill tufts absent. Last pair of dorsal abdominal spiracles positioned at distal ends of short respiratory tubes and are about same size as other spiracles; respiratory tubes much shorter than anal prolegs.
                     
                   
                   
            Dorsal
               Ventral
               


