Species › Insects & Arthropods › Eastern Dobsonfly

Eastern Dobsonfly

Corydalus cornutus

UncommonInsect & Arthropod
Illustration of Eastern Dobsonfly (Corydalus cornutus)

The Eastern Dobsonfly is one of North America's largest insects, with a wingspan reaching 5 inches and males bearing absurdly long, crossed mandibles that look fearsome but are used only in mating competition. Females have shorter, functional mandibles that can deliver a sharp bite. The aquatic larva, the hellgrammite, is prized as fishing bait and is a clean-water indicator species.

Habitat
Rocky streams and rivers with clean water
Diet
Larvae: aquatic invertebrates in stream gravel. Adults: little or no feeding
How common
Uncommon

Best time to see a Eastern Dobsonfly

The best time to see a Eastern Dobsonfly is June–July, when about 69% of U.S. sightings happen, based on 18,111 research-grade iNaturalist observations.

J
F
M
A
M
J
J
A
S
O
N
D

Not certain it is a Eastern Dobsonfly? What bug is this? walks through what to check first and the lookalikes that catch people out.

Recent Eastern Dobsonfly sightings near you

Live, research-grade observations from iNaturalist. Allow location to center the map on you.

Spotted an Eastern Dobsonfly?

Point Huck at any plant, bird, or animal and know for sure - plus a live map of where it is being spotted near you.

Get Huck - free
5,300+species
63national parks
50states

More insects & arthropods

Eastern Forktail
Eastern Forktail
Ischnura verticalis
Eastern Harvestman
Eastern Harvestman
Leiobunum vittatum
Eastern Hercules Beetle
Eastern Hercules Beetle
Dynastes tityus
Eastern Honey Bee
Eastern Honey Bee
Apis cerana
Eastern Lubber Grasshopper
Eastern Lubber Grasshopper
Romalea microptera
Eastern Pine Elfin
Eastern Pine Elfin
Callophrys niphon
Eastern Pondhawk
Eastern Pondhawk
Erythemis simplicicollis
Eastern Subterranean Termite
Eastern Subterranean Termite
Reticulitermes flavipes