Dobsonfly

Map

Flyfishing Entomology

	Life Stage Characteristics

Corydalinae	Dobsonfly
Larva § Lateral gill filaments on abdominal segments 1-8 § Abdominal segment 10 has a pair of prolegs, each bearing a pair of hooks § Large mandibles § Color: black § Size: up to 75 mm (3”) § Instars: 10-11
Pupa § Larva crawls out of water to pupate, so pupa is not available to fish
Adult § Long antenna § Some adults with large sickle-shaped mandibles § No tails § Color: dark gray or brown § Size: 50 mm (2”)

Dobsonflies are in a single subfamily. Dobsonfly larvae are commonly called hellgrammites. They are extremely large, up to 3” in length. They have lateral gill filaments on abdominal segments 1-8, and a pair of terminal segment prolegs, each bearing a pair of hooks, which they use to crawl by hitching themselves backwards. They also have large strong mandibles, which are capable of inflecting a nasty pinch, if care is not taken with handling them.

When it comes time to pupate after nearly three years of growth, the larva crawls out of the water and seeks refuge under logs or stones. As a result, the pupa is not available to fish.

The adults are largely nocturnal and very weak flyers.

Created: 08/04/2004 Last modified: 08/25/2006 www.FlyfishingEntomology.com