Species Insects & ArthropodsEastern 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.

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