Libellulidae Selys - Skimmers

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LAST UPDATED 01/27/2017


Key to Larvae of Michigan Libellulidae
(Modified from
Walker and Corbet 1975 and Westfall and Tennessen 1996)

1a. Abdomen with middorsal hook on Ab9 (Figure 1a1) - Perithemis


Fig 1a1:
Perithemis tenera larva, (12.5x, dorsal view) from Radnor Lake, Davidson Co., TN, collected by Mike Wright on 12 May 1945. UMMZODO-1546.

1b. Abdomen without middorsal hook on Ab9 - 2


2a(1b). Lateral spines of Ab8 equal to, or longer, than middorsal length of Ab9 (Figure 2a1); no middorsal hooks on Ab5-7 (Figure 2a2) - 3

Fig. 2a1 Fig. 2a2
Fig. 2a1:
Tramea lacerata larva (6x, dorsal view), from Radnor Lake, Davidson Co., TN, collected by Mike Wright on 10 April 1936. UMMZODO-1379. Both images taken at 12x.
Fig. 2b1: Ibid.

2b. Lateral spines of Ab8 shorter than (or absent) than middorsal length of Ab9 (picture); or, if with long spines on Ab8, then with dorsal hooks on Ab5-7 - 4
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3a(2a). Epiproct as long or longer than paraprocts (Figure 3a1); dorsal hook present on Ab2-4 (Figure 3a2); lateral spines of Ab8 less than 0.66x the length of those on Ab9 (Figure 3a3); crenations of lateral lobe deep, as deep as wide, though may not be apparent in early instars (Figure 3a4);- Pantala

Fig.3a1Fig.3a2 Fig.3a3 Fig.3a4
Fig. 3a1:
Pantala hymenea larva (12.5x, dorsal view), from Marble Cliffs Pond in Columbus, Franklin Co., OH, collected by Mike Wright on 03 August 1939. UMMZODO-1540.
Fig. 3a2: Ibid. (25x, dorsal view).
Fig. 3a3: Ibid. (12.5x, dorsal view).
Fig. 3a4: Ibid. (12.5x, dorsal view).

3b. Epiproct shorter than paraprocts (picture); dorsal hook absent on Ab2-4 (picture); lateral spines of Ab8 about 0.9x the length of those on Ab9 (picture); crenations of lateral lobe shallow, much wider than deep (picture); - Tramea

Fig. a Fig. b Fig. c Fig. d
Fig x-x:
Tramea lacerata larva, collected from Radnor Lake, Davidson Co., Tennessee by M. Wright on 10 April 1936. Fig a and c taken at 12x, fig b and d taken at 25x.

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4a(2b). No middorsal hooks on abdomen; length of final instar larva < 11 mm (clearly indicated by well-developed wingpads) (Figure 4a1); palpal setae 6 (picture); end of abdomen truncated and very hairy (Figure 4a2) - Nannothemis

Fig. 4a1 Fig. 4a2
Fig. 4a1:
Nannothemis bella larva (3x, dorsal view), from roadside ditch at Juniper Creek, Calhoun Co., Florida, collected on 18 March 1974 by M. J. Westfall, Jr. Specimen loan courtesy of B. Mauffrey, IORI
Fig. 4a3: Ibid, (6x, dorsal view).

4b. Middorsal hooks present or absent; length of final instar larva > 15 mm; palpal setae usually more than 6 - 5
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5a(2b). Eyes confined to anterior fourth of head, capping anterolateral part of head and raised dorsally above contour of head capsule (picture); abdomen long and tapering to an acute point (picture) - 6

5b
. Eyes occupying about half the length of head, more broadly rounded and lateral in position, not protruding above contour of head capsule (picture); body usually short and blunt (picture) - 8
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6a(5a). Distal margin of prementum smooth (crenations visible only at magnification 15x, with spinulose setae not in notches between bases), and apical margin of prementum straight on each side of median line (picture) - Libellula


Fig. x:
Libellula luctuosa larva (25x, dorsal view), from Pond at Clear Creek (Norris Dam), Anderson Co., Tennessee, collected by M. Wright on 21 July 1946. UMMZODO-1994.

6b. Distal margin of prementum clearly crenate (crenations clearly visible at 5x, spinulose setae within notches of crenations), and apical margin of prementum convex on each side of median line (picture) - 7

Fig. a
Fig. a:
Plathemis lydia larva, 12x dorsal view. Collected from the Maple River, Emmet County, Michigan, on 23 August 1953 by E. J. Kormondy. UMMZODO-0967.

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7a(6b). 3 or fewer premental dorsal setae, inconspicuous (picture); middorsal hooks on Ab7-8 (picture); no dark dorsal-lateral brown or black ridges on Ab7-9 (picture) - Ladona

7b
. 8-11 dorsal premental setae on each side of median line (picture); no middorsal hooks on Ab7-8 (picture); Ab7-9 with brown or black, shining, dorsal-lateral ridges (picture) - Plathemis

Fig. a Fig. b
Fig. a-b:
Plathemis lydia larva, dorsal view at 25x and 12x, respectively. Collected from the Maple River, Emmet County, Michigan, on 23 August 1953 by E. J. Kormondy. UMMZODO-0967.

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8a(5b). Apical third of cerci and paraprocts curved strongly downward, best seen in lateral view (picture); lateral spines absent (picture); small, compact larvae, eyes usually with prominent longitudinal stripes (picture) - Erythemis

8b
. Paraprocts and cerci straight or nearly so (picture); lateral spines usually present (picture) - 9
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9a(8b). Middorsal hooks absent (picture), or represented only by prominences on Ab4-9 that bear conspicuous tufts of setae (picture)- 10

9b
. Middorsal hooks present, well-developed - 12
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10a(9a). Tips of lateral spines of Ab9 extending farther caudad than tip of epiproct, longer than middorsal length of Ab9 (picture); dark ridge running mesad from mesoposterior part of eye (picture); antennal segment 6 markedly darker than segment 5 (picture) - Pachydiplax

10b
. Tips of lateral spines of Ab9 not extending beyond tip of epiproct, equal to or shorter than middorsal length of Ab9 (picture); no dark ridge running mesad from mesoposterior part of eye (picture); antennal segment 6 not as above (picture) - 11
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11a(11b). Lateral spine of Ab8 minute, 0.1x or less the middorsal length of Ab8, or absent; lateral spine of Ab9 0.1x-0.5x the middorsal length of Ab9 - Sympetrum

11b
. Lateral spine of Ab8 larger, > 0.3x the middorsal length of Ab8; lateral spine of Ab9 usually 0.5x or more the middorsal length of Ab9 - Leucorrhinia
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12a(9b). Lateral spines of Ab9 long and straight, reaching to or beyond tips of paraprocts and about 2x the middorsal length of Ab9; no middorsal hook on Ab8 (Fig.12a1) - Celithemis


Fig. 12a1: Celithemis fasciata (monomelaena) larva (12.5x, dorsal view), collected from Third Sister Lake, Washtenaw Co., MI, on 12 June 1934 by J. W. Leonard. UMMZODO-0862.

12b. Lateral spines of Ab9 < 2x the middorsal length of that segment, not extending to tips of paraprocts (picture); dorsal hook present or absent on segment 8 (picture) -13
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13a.(13b). Middorsal hook on Ab3 (picture); epiproct paraprocts about equal in length (picture) - Leucorrhinia

13b
. Middorsal hook absent on Ab3 (picture); epiproct distinctly shorter than paraprocts (picture) - Sympetrum
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