East Asia is where most of the Dobsonflies and Fishflies of the world live, but the United States and Canada are home to some 80 species, and many others are found in the Neotropics.
Fishflies and Dobsonflies are streamside creatures that have a fluttery flight. They are large as insects go, often 30 mm or more in length. Two important family characteristics are the presence of ocelli, and the cylindrical shape of the fourth tarsal segment (Borror and White, 1970).
Chauliodes larvae are most common in ponds and swamps; Nigronia and Corydalis larvae are found in creeks or small rivers. All are predaceous (Eaton and Kaufman, 2007).