Dobsonfly (Hellgrammite)

Dobsonflies spend most of their life in the larval stage (click on pictures below, right) during which they are called hellgrammites, and are familiar to anglers who like to use the large larvae as bait. These vicious, primeval creatures reach to 2" to 3" in length, with gills all along the sides of their segmented bodies that allow them to breathe underwater. They are nocturnal (active at night). Hellgrammites are also poor swimmers, but voracious predators. To catch prey, they hide under large rocks and other shelter in fast flowing stretches of streams, creeks and small rivers and attack prey as it swims or crawls past.

Both male and female dobsonflies can reach lengths up to five inches (12.5 cm), measured from the tips of their pincers to the tips of their four wings, which, when not in use, are folded along the length of their walkingstick-like bodies. Their wingspans can be twice as long as their body length, and the wings themselves are densely lined with intersecting veins.

The good news: Hellgramites are an excellent indicator of water quality, living only in well oxygenated, high quality creeks and rivers, such as the Allegheny.