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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Agrypnia (Phryganeidae) of Michigan - Identification

(adapted from Wiggins)

    1a Males
    1b Females 9
    2a(1a) a. Dorsum of Ab9 not extended posteriorly as a roof-like ledge overhanging base of Ab10 Agrypnia deflata (Milne)
    b. Basal segment of inferior appendages elongate and narrow, terminated with a short, heavily sclerotized, tapering process directed ventrad
    c. Apical segment of inferior appendages, when present, slender and finger-Iike, much shorter than basal segment
    2b a. Dorsum of Ab9 extended posteriorly as roof-like ledge overhanging base of Ab10 in some species 3
    b.Inferior appendages varied, but not as above
    c.In species with the basal segment of the inferior appendages narrow and elongate, similar to above, the apical processes are of different type and directed dorsad, with a freely aniculated apical segment always present
    3a(2b) Apical segment of inferior appendages broad and flattened, its mesal surface with a dense vestiture of short dark setae 4
    3b Apical segment of inferior appendages long, thin and generally finger-Iike, and without a dense vestiture of short, dark setae 5
    4a(3a) Ab10 with each posterolateral corner extended into elongate process bearing several stout setae also: In dorsal view, dorsum of Ab9 with a broad mesal excision Agrypnia glacialis Hagen
    4b Ab10 simple, without processes or stout setae also: Basal segment of inferior appendages with two apical processes Agrypnia improba (Hagen)
    5a(4a) Basal segment of inferior appendages extended beyond the point of articulation of the terminal segment into two slender, pointed processes 6
    5b Basal segment of inferior appendages extended beyond point of articulation of the terminal segment as one stout process 9
    6a(5a) Basal segment of inferior appendages with a prominent, finger-Iike ventral process near its base Agrypnia vestita (Walker)
    6b Basal segment of inferior appendages lacking finger-Iike process near its base 7
    7a(6b) a. Ab10 lacking stout, spine-like setae
    Agrypnia straminea Hagen
    b.Inferior appendages with basal segment broad and scoop-like at base
    7b a. Ab10 with stout, spine-like setae 8
    b. Inferior appendages with its basal segment narrow throughout
    8a(7b) Ab10 with median dorsal area thickly set with many short, spine-Iike setae in addition to long, stout setae at its apex Agrypnia macdunnoughi (Milne)
    8b Ab10 lacking a thick median dorsal patch of short setae, but with only 2-3 pairs of stout spine-Iike setae, arising from dorsal surface near its apex Agrypnia colorata (Hagen)

    a. Each half of vulval lobe separate and not combined as single, flattened median lobe, rather straight-sided and strap-like, its ventral keel broad and not flattened in ventral aspect

    Agrypnia deflata (Milne)
    b. Median stalk deep and steep-sided to apex, with apical lobes arising abruptly from dorsal, more or less horizontal, surface of median stalk
    also: Ab10 with lateral and mesal lobes not well developed, appearing as low rounded prominences, mesal lobes separated by broad, shallow median notch
    9b a. Vulval lobe flattened, unified, more or less ovoid or circular in outline, posterior margin excised 10
    b. Median stalk tapered in depth towards apex, vulval lobe smoothly confluent with stalk

    a. Fore wings with moderate to heavy coating of setae, color pattern in most species of dark greyish-brown reticulations over a lighter background, somewhat less intense in certain species

    b. Tibiae and tarsi of first two pairs of legs with alternating bands of light and dark brown
    c. Antennal segments, particularly near base, banded with light and dark brown
    10b a. Fore wings with very light coating of setae, membrane yellowish-brown in most species, sometimes with some light brownish reticulations, streaks or blotches, in certain species with silvery markings, but usually the fore wings overall are rather shiny and transparent 14
    b. Tibiae and tarsi uniform light yellowish-brown
    c. Antennal segments uniform light brown
    11a(10a) Vulval lobe and median stalk enlarged and thickened, base of the median stalk with prominently rounded lateral expansions Agrypnia vestita (Walker)
    11b Vulval lobe and median stalk not greatly thickened 12
    12a(11b) In ventral view, vulval lobe broadly ovoid and rather flat, its posterior margin with two small notches, one on each side of median truncate flap Agrypnia macdunnoughi (Milne)
    12b In ventral view, vulval lobe not broadly ovoid, posterior margin with single, rather broad median notch, occasionally with short median extension 13
    13a(12b) Posterior margin of Ab10 more uniform, mesal lobes not developed at all, lateral lobes short Agrypnia colorata (Hagen)
    13b Posterior margin of Ab10 extended into well-developed mesal and lateral lobes Agrypnia improba (Hagen)
    also: Vulval lobe quadrate in ventral view, its length at least as great as its width
    14a(10b) a. Ab10 with lateral lobes developed into finger-like processes, its ventral portions broad and heavily sclerotized Agrypnia straminea Hagen
    b. Mesal lobes of Ab10 also well developed, and separated from lateral lobes by deep excision
    also: Median stalk of vulval lobe broader and not strongly constricted in ventral view, usually without long setae, and a median ridge not apparent
    14b a. Ab10 with lateral lobes not like stout finger-like processes, but moderately developed, somewhat flattened lobes Agrypnia glacialis Hagen
    b. Mesal lobes of Ab10 only slightly developed, and separated from the lateral lobes by only a shallow emargination
    also: In ventral view, sclerotized hood overhanging the genital opening with rounded, bulging lateral margins


    Wiggins GB. 1998. The caddisfly family Phryganeidae (Trichoptera). University of Toronto Press, Toronto, Canada. xi + 306 p.

Page created: October 15, 2003; Last edited: November 08, 2013 (EB)