hellgrammitid

Hellgrammites are the larval form of dobsonflies, which are large, predatory insects belonging to the family Corydalidae. These larvae are characterized by their dark, segmented bodies, powerful mandibles, and a series of fleshy prolegs along their abdomen. They are aquatic and typically inhabit clean, fast-flowing streams and rivers, where they are an important part of the ecosystem.

Hellgrammites are voracious predators, feeding on a variety of small aquatic invertebrates such as insect larvae, snails, and worms. Their formidable jaws are used to capture and crush their prey. They spend a significant amount of time underwater, usually burrowing into the substrate or hiding under rocks and logs. The larval stage can last for several years, during which the hellgrammite undergoes multiple molts.

When ready to pupate, the hellgrammite will leave the water and seek out a moist, sheltered location on land, often under bark or in decaying wood. It constructs a pupal chamber and transforms into a dobsonfly. The adult dobsonfly is a winged insect, with females being larger than males and possessing a distinct ovipositor. Adult dobsonflies have chewing mouthparts but are not typically predatory and often do not feed at all, focusing instead on reproduction. They are most active at night and are attracted to lights. The life cycle is completed when the female lays eggs, usually in masses on vegetation overhanging the water, and the newly hatched larvae fall into the stream to begin their aquatic life.