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Family Corixidae - Water Boatmen

Desert Corixidae, far from Water! - Graptocorixa Unknown Corixid - Callicorixa audeni 8017402 Water Boatmen Water Boatman Water boatman - Sigara Waterboatman - Trichocorixa Bug
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Hemiptera (True Bugs, Cicadas, Hoppers, Aphids and Allies)
Suborder Heteroptera (True Bugs)
Infraorder Nepomorpha (Aquatic Bugs)
Family Corixidae (Water Boatmen)
Numbers
the largest water bug family, with 125 spp. in 17 genera in our area (all but 1 sp. in the Corixinae)(1) and >600 spp. in 35 genera worldwide(2) arranged in 6 subfamilies(3)
selected local faunas: TBA spp. in Canada(4), ~60 in MI(5), 30 in FL(6), 45 in CA & adjacent states(7), 44 in NH(8), 23 in OK(9), ~43 in TX(10)
Overview of our fauna (* –taxa not yet in the guide; + -non-native):
Family Corixidae
Subfamily Cymatiainae (sic!) Cymatia
Subfamily Corixinae
Size
3-11 mm(1) (1.5-16 mm worldwide(3))
Identification
Body elongate and oval, dorsal surface flattened, with narrow dark crosslines. Front legs short, tarsi 1-segmented and scoop-shaped. Hind legs elongate, oar-like, with fine hairs(11)
The species look very simlar and can be distinguished mainly by male genitalia, protarsi, elytral patterns, etc.
Critical сharacters for genus identification: Identifying corixids can be a daunting task as members of different genera can be superficially similar. For image-based genus-level identification please provide:
1) Both dorsal and ventral habitus shots of preferably dry specimen (water can obscure important features, i.e. the dorsal colour pattern, texture of the hemielytra, etc.)
2) Lateral view. The key diagnostic traits here are the nodal furrow and translucent (pruinose) areas on the claval suture and the area immediately posterior to the nodal furrow.

3) Facial shot showing rostrum details.
4) Shot of the upper ventral half of the insect (showing prothoracic lobes, mesepimeron, and scent glands.
5) Shot of the dorsal abdominal segments (tergites)- sex determination often relies on examination of the dorsal terminal segments; males generally have asymmetrical dorsal terminalia and may or may not have a black spot-like structure called a "strigil" depending on genus; females have symmetrical terminalia.
6) Palae, especially of the male- of some importance in genus identification but generally more critical in species ID.
Size may also be important, as some genera have a specific size range.
Keys to genera in(12)(5)(13); keys to spp. in(14). Species identification requires examination of specific features, e.g. genitalia, male palae (front tarsi), ventral structures, etc. Species of some genera may be identifiable from photos, but spp. of Sigara, Hesperocorixa, etc. large genera are unlikely to be identifiable.
Keys to spp.: Michigan(5), FL(6); key to AB genera in(13)
Range
Worldwide and throughout NA
Habitat
Common in ponds. Also found in birdbaths. A few species live in streams, and others are found in brackish pools along the seashore above the high tidemark.
Food
Algae, detritus, other aquatic organisms (mosquito larvae, brine shrimp)(2); a few (uniquely among Hemiptera) consume small particles of solid food(1)
Life Cycle
eggs are cemented to underwater objects, sometimes forming a dense mat(1)
Remarks
Males make sounds by rubbing their front legs against the front of their head(1)
Unlike Notonectidae, Corixidae do NOT bite.
Adults fly to lights, sometimes in great numbers
See Also
Backswimmers (Notonectidae) (NB: Corixidae swim dorsal side up, Notonectidae swim upside-down)
Works Cited
1.American Insects: A Handbook of the Insects of America North of Mexico
Ross H. Arnett. 2000. CRC Press.
2.Biodiversity of the Heteroptera
Henry T.J. 2009. In: Foottit R.G., Adler P.H., eds. Insect biodiversity: Science and society. Oxford: Wiley-Blackwell: 223-263.
3.Australian Faunal Directory
4.Checklist of the Hemiptera of Canada and Alaska
Maw, H.E.L., R.G. Foottit, K.G.A. Hamilton and G.G.E. Scudder. 2000. NRC Research Press.
5.Bright E. (2002-2011) Aquatic Insects of Michigan
6.Identification manual for the aquatic and semi-aquatic Heteroptera of Florida
Epler J.H. 2006. FL Dept. of Environmental Protection, Tallahassee, FL. 186 pp.
7.List of freshwater macroinvertebrate taxa from California and adjacent states
Richards A.B., Rogers D.C. 2011. Southwest Association of Freshwater Invertebrate Taxonomists (SAFIT). 266 pp.
8.University of New Hampshire Insect and Arachnid Collections
9.Checklist of the Hemiptera of Oklahoma
10.Ziser S.W. (2008-) The aquatic invertebrates of Texas
11.A Field Guide to Insects
Richard E. White, Donald J. Borror, Roger Tory Peterson. 1998. Houghton Mifflin Co.
12.Aquatic Insects of North America
R. W. Merritt, K. W. Cummins, M.B. Berg. 2008. Kendall/Hunt.
13.Clifford H.F. (1991) Aquatic invertebrates of Alberta
14.Corixidae of the Western Hemisphere
Hungerford, Herbert Barker. 1948. University of Kansas Publications.