Insects

Hellgrammite (Dobsonfly Larva)

(Corydalus cornutus)

Species Description

**Description:** The aquatic larvae of the Dobsonfly, featuring dark, segmented bodies and large, powerful pincers.

**Size:** Can grow up to 4 inches long.

**Sexual Dimorphism:** Larvae are similar, but the winged adults show extreme differences: males have massive sickle-mandibles, females have short, biting pincers.

**Behavior:** Fierce predators and a "holy grail" bait for bass fishermen. They require high oxygen levels to survive.

**Habitat:** Under rocks in fast-moving, clean sections of the Allegheny River.

💡 Fun Facts

Hellgrammites have gills on their abdomen, but they also have "spiracles" that allow them to breathe air if they crawl out of the water.
**Description:** The adult version of the Hellgrammite. They are large, intimidating insects with four smoky, veined wings and a prehistoric appearance.**Size & Weight:** Wingspan up to 5 inches.**Sex Differences:** Extreme! Males have massive, sickle-shaped mandibles (tusks) used for fighting other males. Females have short, powerful pincers that can actually deliver a painful bite.**Habits:** They are nocturnal and attracted to lights. As adults, they live only a few days to a week, just long enough to mate and lay eggs back in the water. Despite their scary look, the males' "tusks" are too long to actually bite humans!
The winged adult of the Hellgrammite. Males have massive, sickle-shaped tusks.
The transitional stage between the aquatic larva and the winged adult; found in chambers dug into damp soil near the riverbank.
Adult Dobsonflies are mostly nocturnal and are so clumsy in flight that they are often seen bumping into lights and porch screens in mid-summer.