adult dobsonfly is a large dark flying
insect. Most dobsonfly species are nocturnal. Males of some species have
mandibles which are tusklike. They can bite.
nymph, known as hellgrammite,
is predaceous, feeding on smaller aquatic invertebrates. They are large
larvae up to 3 inches (7.5 cm) in length, which strong jaws and legs and
seven or eight pairs of gill filaments attached to the abdomen, which look
like small legs. They are most often found in fast moving streams. Fisherman
use the hellgrammites for bait.