Corduliidae Selys - Emeralds


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Key to Larvae of Michigan Corduliidae
(Adapted from Walker and Corbet 1975 and Westfall and Tennessen 1996)

1a. Middorsal hooks absent or reduced to low knobs (picture) - 2

Fig. x.

1b. Middorsal hooks present, well-developed on some abdominal segments (picture) - 4

2a(1a). Sides of thorax uniformly colored - Somatochlora (in part)

2b. Sides of thorax with dark, broad longitudinal strip (picture) - 3


Fig. x. Cordulia shurtleffi larva, collected from Lake Genevieve (near Ann Arbor), Washtenaw County, Michigan by M. F. O'Brien on 05 April 1998. UMMZODO-1896.
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3a(2b). Mature larval length > 20 mm; dorsal abdominal hooks absent, or if vestigial, highest on Ab8 (picture); lateral spines of Ab9 about 0.2x the length of that segments lateral margin (not including the spine) - Cordulia

Fig. x. Fig. x.
Fig. x-x. Cordulia shurtleffi larva, collected from Lake Genevieve (near Ann Arbor), Washtenaw County, Michigan by M. F. O'Brien on 05 April 1998. UMMZODO-1896.

3b. Mature larval length < 19 mm; dorsal abdominal hooks stubby but distinct, highest on Ab5 (picture); lateral spines of Ab9 about 0.4x the length of that segmentís lateral margin (not including the spine) - Dorocordulia
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4a. Without lateral spines on Ab8 - Williamsonia

4b. With lateral spines on Ab8 - 5
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5a(4b). Crenations on distal margin of labial palpi nearly semicircular or even more deeply cut (picture); lateral spines on Ab8 and Ab9 nearly equal in length, those on Ab8 divergent - Neurocordulia

Fig. xa Fig. xb
Fig. xa: Neurocordulia yamaskanensis exuvia (25x, frontal view), from Paint River, Iron Co., Michigan, collected by D. Cuthrell and D. Hyde (MNFI) on 19 June 1996. UMMZODO-1783. Fig.xb: Neurocordulia yamaskanensis larva, collected from Big Platte River, Benzie County, Michigan, by Brown and Ball, on 03 July 1940. UMMZODO-1454.

5b. Crenations on distal margin shallower than semicircle (picture); lateral spines on Ab9 equal or longer than those on Ab8, those on Ab8 not divergent (fig) - 6


Fig. x: Epitheca cynosura larva (50x, dorsal view), from Hess Pond, Franklin Co., Columbus, Ohio, collected by M. Wright on 26 May 1939. UMMZODO-2005.

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 6a(5b). Lateral spines on Ab9 at least 2.0x as long as those on Ab8, at least equal to middorsal length of Ab9 - Epitheca

6b. Lateral spines on Ab9 about equal to those on Ab8, less than the middorsal length of Ab9 - Somatochlora
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