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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- Aquatic Insects of Michigan
Glossosomatidae (Saddle-case makers) of Michigan - Identification
Introduction
There are three genera 3 genera found in Michigan, Glossosma Curtis (3 species), Agapetus Curtis (2+1 species) and Protoptila Banks (3+1 species). A species key to pupae and larvae (except Glossosoma) is currently unavailable.
Adults (adapted from Leonard and Leonard 1949, Ross 1941, 1944, Schmid (1982, 1998), and Wymer and Morse (2000)
| 1a | a. Protibiae without spurs (0,4,4 or 0,3,3) |
Protoptila Banks, 3 |
| b .Front and hind wings long and very narrow, venation reduced and faint | ||
| also: phallic apparatus between preanal appendages; male Ab8 sternite platelike, elongated posteriorly; in ventral view, vaginal apparatus with a very long rod | ||
| 1b | a. Protibiae with two spurs (2,4,4) | 2 |
| b. Front and hind wings fairly evenly elliptical, veneation complete or almost complete | ||
| 2a(1b) | a. Hind wing with the discoidal cell closed, and the R1 long and ending at the wing margin |
Glossosoma Curtis, 9 |
| b. Dorsum of head with neither pair of warts connected by transverse epicranial sutures | ||
| also: Aedeagus small with its vertical parameres completely concealed in the genital cavity, and a tendon connecting the phallotheca to the preanal appendages | ||
| 2b | a. Hind wing with the discoidal cell open, and the R1 short, ending at vein R2+3 | Agapetus Curtis, 14 |
| b. Dorsum of head with both pairs of warts connected by transverse epicranial sutures | ||
| 3a(1a) | Males |
4 |
| 3b | Females | 7 |
| 4a(3a) | In ventral view, Ab8 sternite scoop-shaped, large and weakly produced posteriorly, and not produced into a bifid process |
Protoptila erotica Ross |
| 4b | In ventral view, Ab8 sternite strongly produced posteriorly and produced into a bifid process | 5 |
| 5a(4b) | In ventral view, Ab8 sternite with the apicolateral corner produced into a brushy lobe, and with the apex with a large and wide median emargination |
Protoptila tenebrosa (Walker) |
| 5b | In ventral view, Ab8 sternite with the apicolateral corner angulate, not produced, and with its apex more slender | 6 |
| 6a(5b) | Lateral spine (parameres) of aedeagus stout, short, and abruptly angled upward near its apex |
Protoptila maculata (Hagen) |
| 6b | Lateral spine (parameres) of aedeagus slender, long, and only gradually curved, abruptly narrowed at its base | Protoptila lega Ross |
| 7a(3b) | a. In ventral view, internal plate of Ab9 tergite with a dorsal, bandlike prolongation which is joined to the base of Ab10 tergite |
Protoptila maculata (Hagen), Protoptila lega Ross |
| b. apicolateral lobes of Ab8 sternite long, trianguloid | ||
| 7b | a. In ventral view, internal plate of Ab9 tergite without a dorsal prolongation | 8 |
| b. Apicolateral lobes of Ab8 sternite narrow | ||
| 8a(7b) | In ventral view, internal sternal "whip" attached to a small, projecting, mesal sclerite |
Protoptila tenebrosa (Walker) |
| also: Lobes of Ab10 tergite conical | ||
| 8b | a. In ventral view, internal sternal "whip" attached to a large, rounded plate which spans almost the entire width of the segment | Protoptila erotica Ross |
| 9a(2a) | Males |
10 |
| 9b | Females | 12 |
| 10a(9a) | Inferior appendages each single, clavate |
Glossosoma intermedium (Klapálek) |
| 10b | Inferior appendages each with two or more branches | 11 |
| 11a(10b) | a. Inferior appendages each with two branches |
Glossosoma nigrior Banks |
| b. Preanal appendages each with an irregular incision in the posteroventral margin, and without a dorsal hook | ||
| 11b | a. Inferior appendages each with three branches | Glossosoma lividum (Hagen) |
| b. Preanal appendages not incised posteroventrally, but with a dorsal hook | ||
| 12a(9b) | a. Ab8 broadly and deeply incised posterodorsally and posteroventrally, and lobed posterolaterally |
Glossosoma nigrior Banks |
| b. Spermathecal sclerite clavate | ||
| 12b | a. Ab8 not incised dorsally, and with a quadrate or acute incision posteroventrally | 13 |
| b. Spermathecal sclerite not clavate | ||
| 13a(12b) | a. Ab8 with a broad, nearly quadrate incision posteroventrally |
Glossosoma lividum (Hagen) |
| b. Spermathecal sclerite rectangular | ||
| 13b | a. Ab8 with a deep, narrow cleft posteroventrally | Glossosoma intermedium (Klapálek) |
| b. Spermathecal sclerite tapered | ||
| [note: description of the female of Agapetus tomus Ross has not been published, but associated female specimens from Michigan have been found and a description is forthcoming] | ||
| 14a(2b) | Males |
15 |
| 14b | Females | 17 |
| 15a(14a) | In lateral view, inferior appendage with its apical (posterior) margin medially emarginate, with the dorsal and ventral corners produced into a sharp but short point |
Agapetus tomus Ross |
| 15b | In lateral view, inferior appendage with its apical margin not with largely medially emarginated, but either largely rounded or trilobed | 16 |
| 16a(15b) | In lateral view, basal portion of the inferior appendage clearly narrower than its apical (posterior) portion, which is largely rounded, and only a low, undulant ridge on its inner face |
Agapetus rossi Denning |
| 16b | In lateral view, inferior appendage narrowed in the basal portion, considerably wider at its apical portion which is often more strongly trilobed, and with a hook arising from the inner face | Agapetus hessi Leonard and Leonard |
| 17a(14b) | In lateral view, the lower basal angle of Ab8 forms a large, prominent and convex lobe |
Agapetus hessi Leonard and Leonard |
| 17b | In lateral view, the lower half of the basal portion of Ab8 is largely concave, with the ventral basal portion forming an acute point | Agapetus rossi Denning |
Pupae (from Ross 1944)
| 1a | a. Apical inner tooth of mandibles 0.5x long as apical blade and subparallel with it | Protoptila Banks, no species key currently available |
| b. Mandibles in repose over-reaching side of head | ||
| c. Body length <4 mm | ||
| 1b | a. Apical inner tooth of mandibles much shorter | 2 |
| b. Mandibles in repose not reaching side of head | ||
| c. Body length > 5 mm | ||
| 2a(1b) | a. Apical inner tooth of mandibles only slightly larger than basal one | Agapetus Curtis, no species key currently available |
| b. Posterior (apical) abdominal segments only slightly curled ventrad | ||
| 2b | a. Apical inner tooth of mandibles many times larger than basal one | Glossosoma Curtis, no species key currently available |
| b. Posterior (apical) abdominal segments curled ventrad and slightly forward | ||
Larvae
(adapted from Wiggins (1996), Wymer and Morse (2000))
| 1a | a. Mesonotum without sclerites | Glossosoma Curtis, 3 |
| b. Head with ventromesal margins of genae thickened, median ventral ecdysial line approximately as long as each divergent branch enclosing ventral apotome | ||
| c. Anal opening bordered on each side by dark, sclerotized line | ||
| also: Pronotum in lateral view about one-third excised anterolaterally to accommodate coxa; venter of Ab8 lacking setae | ||
| 1b | a. Mesonotum with two or three sclerites | 2 |
| b. Head with ventromental margins of genae not thickened, median ventral ecdysial line approximately 1.5x longer than each divergent branch | ||
| c. Anal opening usually lacking dark, sclerotized line on each side | ||
| 2a | a. Mesonotum with three sclerites | Protoptila Banks, no species key available |
| b. Head with ventral apotome reduced to slender, V-shaped sclerite | ||
| also: Tarsal claws with basal seta long and slender, arising from side of stout process at base of claw | ||
| 2b | a. Mesonotum with two sclerites | Agapetus Curtis, no species key available |
| b. Head with anterior ventral apotome not slender as above | ||
| 3a | Pronotum without a small black spot above the forecoxa | Glossosoma lividum (Hagen) |
| 3b | Pronotum with a small black spot above the forecoxa | 4 |
| 4a | Intersegmental fold between thorax and abdomen posterior of each metathoracic epimeron with small sclerite | Glossosoma nigrior Banks |
| 4b | Intersegmental fold between thorax and abdomen posterior of each metathoracic epimeron without small sclerite | Glossosoma intermedium (Klapálek) |
References
-
Leonard JW, Leonard FA. 1949. Noteworthy records of caddis flies from Michigan, with descriptions of new species. Occasional Papers of the Museum of Zoology, University of Michigan 520:1-8, 5 pls.
Ross HH. 1941. Descriptions and records of North American Trichoptera. Transactions of the American Entomological Society 67:35-126, 13 pls.
Ross HH. 1944. The Caddis Flies, or Trichoptera, of Illinois. Bulletin of the Illinois Natural History Survey 23(1):1-326.
Schmid F. 1982. Revision des Trichoptčres canadiens. II. Les Glossosomatidae et Philopotamidae (Annulipalpia). Mémoires de la Société entomologique du Canada 122:1-83.
Schmid F. 1998. The Insects and Arachnids of Canada. Part 7. Genera of the Trichoptera of Canada and Adjoining or Adjacent United States. NRC Research press, Ottawa, Ontario, Canada. 319 pp.
Wiggins GB. 1996. Larvae of the North American caddisfly genera (Trichoptera). University of Toronto Press: Toronto, Ontario. 457 pp. + xiii.
Wymer DA, Morse JC. 2000. Larva, pupa, and adults of Glossosoma nigrior (Trichoptera: Glossosomatidae) with a review of the eastern North American species of Glossosoma. Entomological News 111(3):149-158.
Page created: May 12, 2003; Last edited: November 07, 2013 (EB)