Epitheca Burmeister,1839(Corduliidae) - Baskettails
Fig. 1: Epitheca spinigera larva (6x, dorsal view), from an unknown locality inMontmorency Co.,
Michigan, collected by C. L. Hubbs in July, 1925.UMMZODO-0310.Notes -Michigan SpeciesList - Key -References
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Page last updated: 21 July1998 (EB)
Notes on theMichigan Species of Epitheca
Walker(1966) combined Tetragoneuria andEpicordulia as subgenera of Epitheca, though somestill recognize the former two as valid genera (e.g., Garrison 1991). Epitheca (Fig. 1) is a Nearctic and Palearctic genus of 10species, of which 4 are found in Michigan (see Maps 1-4,below).
Much of what we know about larval biology comesfrom Needham andHeywood (1929) and especiallyKormondy(1959), the latter who wroteextensively on Tetragoneuria systematicsand the subgenus' biology and ecology in Michigan. Larvae live inshallow water close to shore. Because of egg-laying habits offemales, dense populations of early-instar larvae can be found, butthese soon decline with inter- and intra-specific competition to aabout 4 or 5 individuals per square meter. Early instars aresprawlers and active hunters, with later instar larvae becoming moresendentary, increasing the depth at which they burrow themselves insubstrates. Larvae cease feeding rougly 1 (spring) or 2 to 3 (fall)weeks before emergence.
Larvae of E.canis appear limited to bog-marginedlakes and ponds and their acidic discharges, and emergence usuallyoccurs in mid to late May. These habitats are usually avoided by theother three species, which tend to prefer marshy or grassy borders oflakes and slow streams. Emergence for these three species also occurslater, from the end of May through June.
Other links with information on the biology orecology of larval Epitheca:back totop
Briefhabitat notes from Ottawa (Ontario, Canada) >>http://www.cyberus.ca/~jdsankey/odon2.html
Maps 1-4: County distribution of Epitheca spp. inMichigan
To enlarge, click on the desired mapEpitheca (subgenus Epicordulia)princeps Hagen, 1861 - Prince Baskettail - Map 1
Epitheca (subgenus Tetragoneuria)canis(McLachlan,1886) - Beaverpond Baskettail - Map2
Epitheca (subgenus Tetragoneuria)cynosura(Say,1839) - Common Baskettail - Map3
Epitheca (subgenus Tetragoneuria)spinigera(Selys,1871) - Spiny Baskettail - Map 4back totop
Key toMature Larvae of Michigan Epitheca
(Adapted from Kormondy 1959 and Walker and Corbet1975)
1a. Distal half of dorsalsurface of prementum heavily setose; palpal setae usually 4, rarely 5(Fig. 2) - Subgenus Epicordulia,E. princeps
Fig. 2: Epithecaprinceps larva (25x, dorsalview), from Radnor Lake, Davidson Co., Tennessee, collected by M.Wright on 05 May 1945. UMMZODO-1903.
1b. Distalhalf of dorsal surface of prementum with few very small setae; palpalsetae usually 6-7, rarely 8 (Fig. 3) - Subgenus Tetragoneuria- 2
Fig. 3: Epitheca spinigera larva (25x, dorsal view), from an unknown locality inMontmorency Co., Michigan, collected by C. L. Hubbs in July, 1925.UMMZODO-0310.
2a.(1b). Lateral spine ofabdominal segment. 9 short, barely attaining the level of the tips ofthe anal appendages (epiproct and paraprocts) (Fig. 4) -E. canis
Fig. 4: Epitheca canis larva (12x, dorsal view), from Rose Lake, Clinton Co.,Michigan, collected by G. Rung on 19 April 1960. UMMZODO-2006.
2b. Lateralspine of abdominal segment 9 long, extending beyond the level of thetips of the anal appendages, usually by twice its length (Fig. 5) -3
Fig. 5: Epitheca spinigera larva (12x, dorsal view), from an unknown locality inMontmorency Co., Michigan, collected by C. L. Hubbs in July, 1925.UMMZODO-0310.
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Caution - thiscouplet may not always be reliable, and, particularly for less-maturelarvae, distinguishing species may not be possible.
3a.(2b). Premental setaeusually not more than 10, palpal setae usually 6 (Fig. 6) -E. cynosura
Fig. 6: Epithecacynosura larva (25x, dorsalview), from Hess Pond, Franklin Co., Columbus, Ohio, collected by M.Wright on 26 May 1939. UMMZODO-2005.
3b. Prementalsetae usually not less than 11, palpal setae usually 7-8 (Fig. 7) -E. spinigera
Fig. 5: Epitheca spinigera larva (25x, dorsal view), from an unknown locality inMontmorency Co., Michigan, collected by C. L. Hubbs in July, 1925.UMMZODO-0310.
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Burmeister, H.1839. Handbuch der Entomologie. Vol 2. Enslin: Berlin, pp397-1050.
Garrison, R. W.1991. A synonymic list of the New World Odonata. Argia 3(2):1-30.
Hagen, H. A. 1861.Synopsis of the Neuroptera of North America, with a list of the SouthAmerican species. SmithsonianMiscellaneous Collections4:1-347.
Kormondy, E. J.1959. The systematics of Tetragoneuria, based onecological, life history, and morphological evidence (Odonata:Corduliidae). MiscellaneousPublications, Museum of Zoology, University ofMichigan 107:1-79.
McLachlan, R.1886. Two new species of Cordulina. Entomologists' Monthly Magazine 23:104-105.
Needham, J.G. and H. B. Heywood. 1929. A Handbook of the Dragonflies of NorthAmerica (Anisoptera). C. C. Thomas: Springfield, Illinois. 378pp.
Say, T. 1839.Descriptions of new North American neuropterous insects andobservations on some already described by (the late) Th. Say.Journal of the Academy of NaturalScience of Philadelphia 8:9-46.
Selys-Longchamps, M.E. de. 1871. Synopsis des Cordulines. Bulletin de l'Académie royale des Sciences deBelgique (2)31:238-316.
Walker, E. M. 1966.On the generic status of Tetragoneuria andEpicordulia (Odonata: Corduliidae). Canadian Entomologist98:897-902.
Walker, E. M., and J.S. Corbet. 1975. The Odonata of Canada and Alaska, Vol. 3. Universityof Toronto Press: Toronto, Ontario. xvi + 308.back totop