Eastern Dobsonfly (Hellgrammite)
Adults are large, soft bodied, usually a drab gray, black or brown, with prominent pincers and long antennae. Wings with conspicuous veins, usually folded down the length of the body when at rest. Pincers (mandibles) of females rather stubby and capable of inflicting a painful bite. Mandibles of males very long, tusklike and incapable of hurting people due to lack of leverage.
Larvae are aquatic, somewhat flattened and usually some shade of brown or tan. Some people think they look like centipedes. The head is equipped with a pair of sharp pincers that can deliver a painful bite. The thorax has 3 pairs of legs. The segmented abdomen has 8 pairs of leglike gill filaments extending from the sides. There is a pair of hooked, leglike appendages at the hind tip; these help keep the animal from being swept away in the water current.