Aquatic Insect #6 ID?

Discussion in 'Fly Fishing Entomology' started by Taxon, May 26, 2012.

  1. Taxon

    Taxon Moderator Staff Member


    This aquatic insect was collected from the South Fork Snoqualmie River. Can you identify it by any of the following?

    Order common name:
    Order taxonomic name:
    Family common name:
    Family taxonomic name:
    Genus taxonomic name:
    Species taxonomic name:
  2. jwg

    jwg Active Member

    Looks like a mayfly nymph

    Order Ephemeroptera (Mayflies)

    Family Leptophlebiidae - Pronggilled Mayflies

    » Genus Paraleptophlebia (Blue Quills and Mahogany Duns)

    I am thinking the forked nonfeathery gills is a key clue
  3. jwg

    jwg Active Member

    Given the tusks I am going to say

    Species bicornuta (Mahogany Dun)

    Here is what Hafele says

    "Recognizing Paraleptophlebia from other mayflies is relatively easy. The most distinctive feature of nymphs is their slender forked (often called “tuning fork”) gills on abdominal segments 1-7. Nymphs also have three prominent tails of equal length. Nymphs overall appear rather delicate, especially when compared to the more robust nymphs of the family Ephemerellidae. Two western species, P. bicornuta and P. packi, have unique mandibles that form large sickle shaped tusks projecting out in front of the head. Mature nymphs have well formed black wingpads and reach lengths of six to about ten millimeters excluding their tails (1/4 – 3/8 inches). Most nymphs will be light tan to brown in color.
  4. Taxon

    Taxon Moderator Staff Member

    Good job, Jay.


    Lifestage: nymph (jwg)
    Order common name: Ephemeroptera (jwg)
    Order taxonomic name: Mayflies (jwg)
    Family common name: Leptophlebiidae (jwg)
    Family taxonomic name: Pronggilled Mayflies (jwg)
    Genus common name: Blue Quills and Mahogany Duns (jwg)
    Genus taxonomic name: Paraleptophlebia (jwg)
    Species taxonomic name: bicornuta (jwg)