Aquatic Insects of Michigan

by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment
University of Michigan

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Mystacides (Leptoceridae) of Michigan - Identification


Two of the three known Nearctic species - M. sepulchralis (Walker) and M. interjecta (Banks) - are found in Michigan, a third species (M. alafimbriata Hill-Griffin is found in the northern Rockies and Sierra Nevadas northwards into British Columbia. The keys below are adapted from Yamamoto and Wiggins 1964 and 1966.


    1a Males 2
    1b Females 3
    2a(1a) a. Posteromesal process of Ab9 sternum divided to form a bifurcate structure, notch broadly U-shaped with the arms long and slender Mystacides sepulchralis (Walker)
    b. Ab10 divided into a group of three sinuate blades
    2b a. Posteromesal process of Ab9 sternum undivided, with only a slight notch at the apex Mystacides interjecta (Banks)
    b. Ab10 divided into two symmetrical processes
    3a(1b) a. Apex of the subgenital plate not greatly extended, the posterior margin with several short simple lobes Mystacides interjecta (Banks)
    b. Lateral lobes of Ab9 markedly narrowed at the base
    3b a. Apex of the subgenital plate extended, the posterior margin with two conspicuous posteromesal lobes, separated by a mesal excision Mystacides sepulchralis (Walker)
    b. Lateral lobes of Ab9 broader at the base
    also: In ventral view, posterolateral corners of the subgenital plate broadly rounded, and the posterior edge of the subgenital plate sloping gradually toward the posteromesal lobes


    1a Abdominal segments with single gill filaments Mystacides interjecta (Banks)
    1b Abdominal segments without gills Mystacides sepulchralis (Walker)

Mature Larvae

    1a a. Larvae with single gill filaments on abdominal segments Mystacides interjecta (Banks)
    1b a. Larvae without gill filament on abdominal segments Mystacides sepulchralis (Walker)

Page created: October 20, 2003; Last edited: November 08, 2013 (EB)