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Stonefly Species Pteronarcys dorsata (Giant Black Stonefly)

Pictures Below
This is the largest common eastern stonefly. It's quite abundant in places, but not to the extent of its western counterparts, and since most of its activity is at night it is generally less important. Nevertheless, nymph imitations produce some very large trout, and lucky or very locally knowledgable anglers may find good fishing to the egg-laying adults.  

Where & When

Regions: East, Midwest

Time Of Year (?): Late April through late June

Hatching Behavior

Time Of Day (?): Overnight; some dawn/dusk overflow

Habitat: Fast water

Egg-Laying Behavior

Time Of Day: Overnight; some dawn/dusk overflow

Habitat: Riffles
I have watched Pteronarcys dorsata adults gather at treetop level above the riffles a hundred yards upstream from a slow stretch of water that held a tremendous swarm of Hexagenia limbata spinners thirty minutes later. I never saw more than one or two on the water, and the egg-laying supposedly happens well after dark.

Pictures of 3 Stonefly Specimens in the Species Pteronarcys dorsata:

Pteronarcys dorsata (Giant Black Stonefly) Stonefly NymphPteronarcys dorsata (Giant Black Stonefly) Stonefly Nymph View 3 PicturesPteronarcys nymphs live for two years before maturing. This small one is in its first year.
Collected March 10, 2004 from unknown in Wisconsin
Added to by Troutnut on January 19, 2006

1 Video of Pteronarcys dorsata Stoneflies:

Date ShotFeb 7, 2004
Date AddedMar 31, 2006

Recent Discussions of Pteronarcys dorsata

Question 7 Replies »
Posted by Max29 on Jan 29, 2008
Last reply on Jan 30, 2008 by Taxon
Are stoneflies and salmonflies the same thing or are they just related because here in the mid west we have the stonfly hatch and if they are related the stonfly could be called the salmonfly and the salmonfly hatch is only in the west because I have trouble because I want to become a better insect identifier when it comes to fishing because i went to other sites that so a stonefly is a stonefly and a salmonfly is a salmon fly but yet you say stonefly nymph but in parenteseses you have american salmonfly so is there really no such thing as a salmonfly but it is rather called a stonefly.

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