Hellgrammite

The Hellgrammite is the larva stage of life of the Dobsonfly. They can be as long as 3 inches and they can live as long as 4 years in the larva stage. The hellgrammites are dull colored larvae with gill filaments and feathery gill clusters along the sides of the abdomen and they have two hooks on the end of the abdomen. The adult Dobsonfly is a very large fly that resembles a stonefly. However, you will not have any difficulty in distinguishing them from the stonefly nymph since the hellgrammites will pinch you noticeably! They hide in the stream bed under flat rocks that are located in fairly shallow fast moving water.

The adult Dobsonfly is nocturnal in nature making it unusual to find one. She has only a few days to deposit her eggs in darkness on the underside of leaves, or the small stems of vegetation. The eggs hatch into larvae and fall off into the water where they live a few years until they hatch. The larvae are veracious predators that eat other insects and other small creatures. 

The hellgrammites when dislodged are graceful swimmers and especially attractive food for the trout or just about any other type of fish. The hellgrammites habitat is slightly warmer water at the mid level of lower elevations. However when the hellgrammite fly is fished in this environment it can be deadly.