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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Hydroptilidae of Michigan - Identification

[under construction]

Keys to the Mature (5th Instar) Larvae of Michigan Hydroptilidae
(adopted from Morse and Holzenthal 2007)

1a Abdomen dorsoventrally depressed also: Ab5-6 usually abruptly broader than other abdominal segments in dorsal aspect; case depressed, oval, made of silk with a small circular opening near each end, fastened to rock surface; basal seta of tarsal claw on each leg much shorter and thinner than the claw Leucotrichia Mosely
1b Abdomen laterally compressed 2

2a(1b) Tarsal claws stout and abruptly curved, each with a thick, pointed basal seta also: Dorsal abdominal setae thin, without basal sclerites; dorsal rings indistinct; 2 elliptical valves of silk case with few or no inclusionsStactobiella Martynov
2b Tarsal claws slender, gradually curved, each with a thin, pointed basal seta or seta apparently absent 3

3a(2b) Protibiae each with a prominent ventral lobe bearing short, stout setae 4
Protibiae lacking prominent ventral lobes, their setae - if present - normal 7

4a(3a) Thoracic legs approximately the same length 5
Middle and hind legs much longer than the forelegs 6

5a(4a) a. Gills absent from the posterior end of the abdomen b. Case protable, laterally compressed, usually consisting of 2 silk valves covered with sand or occasionally filamentous algae, but sometimes dorsoventrally depressed, with the dorsal valve carried like a tortoise shell and ventral sheet flat Ochrotrichia Mosely
5b a.3 filamentous gills arising from the posterior end of the abdomen, 1 from the dorsomedian position on Ab9, the other 2 from lateral sclerites of the anal prolegs b. Case portable, compressed, consisting of 2 silken valves usually covered with sand grains or sometimes diatoms also: Base of each mesotarsal claw smoothly contoured with its apicoventral margin Hydroptila Dalman

6a(4b) a. Antennae long and slender, longer than the diameter of the cluster of stemmata b. Ventral lobe of each protibia parallel-sided c. Case portable, compressed, entirely of silk, shaped like a flask and opened posteriorly Oxyethira Eaton
6a(4b) a. Antennae shorter than the diameter of the cluster of stemmata b. Ventral lobe of each protibia triangular c. Case portable, compressed, incorporating filamentous algae in concentric circles Agraylea Curtis

7a(3b) Anal prolegs elongate and cylindrical, projecting prominently beyond the general outline 8
Anal prolegs short, conforming to the general body outline and not projecting 9

8a(7a) a. Mesotibiae each with a pair of short, stout ventral setae located apically, or nearly apically b. Case portable, made of silk or including soft mineral material, tapered posteriorly, cylindrical but usually with longitudinal or transverse and longitudinal ridges Mayatrichia Mosely
8b a. Mesotibiae each with a pair of ventral setae located about 1/3 the distance from the apex b. Case portable, made with fine sand grains, cylindrical Neotrichia Morton

9a(7b) a. Most abdominal segments with prominent, pointed, dorsal and ventral projections b. Flat silk case open posteriorly, reduced to small circular opening anteriorly Ithytrichia Eaton
9b a. Abdominal segments without dorsal and ventral projections b. Case of silk, with longitudinal ridges Orthotrichia Eaton


    Morse JC, Holzenthal RW. 2007. Trichoptera Genera, pp. 481-552 in Merritt RW, Cummins KW, Berg MB, An Introduction to the Aquatic Insects of North America, Fourth Edition. Kendall/Hunt Publishing Company, Dubuque, Iowa, USA.