Length: 30-48 mm
Unlike the related Spring Fishfly and Summer Fishfly, the Eastern Dobsonfly has numerous white dots on the wings, and the males have huge mandibles. The mandibles of the females (pictured here) are not nearly as large, but are impressive enough. Comparing Fishflies and the Eastern Dobsonfly, there is also a difference in the dorsal outline of head and thorax, with the head flaring out from the pronotum more abrubtly in the Eastern Dobsonflies.
Dobsonflies in the genus Corydalis are large, impressive insects. Their larvae are aquatic, and hence the adults are most often found near water. They are often noticed when they are attracted to outdoor lights. The Eastern Dobsonfly in widespread in the eastern United States and Canada; 33 other species are found in the Neotropics and north into the southwestern U.S. (Contrera-Ramos, 2011).
American Insects site