Libellulidae Selys -Skimmers


Key to Larvaeof Michigan Libellulidae
(Modified from
Walker and Corbet1975 and Westfall andTennessen 1996)

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


Fig 1a1:
Perithemistenera larva, (12.5x, dorsalview) from Radnor Lake, Davidson Co., TN, collected by Mike Wright on12 May 1945. UMMZODO-1546.

1b. Abdomenwithout middorsal hook on Ab9 - 2


2a(1b). Lateral spines ofAb8 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: Tramealacerata larva (6x, dorsalview), from Radnor Lake, Davidson Co., TN, collected by Mike Wrighton 10 April 1936. UMMZODO-1379. Both images taken at 12x.
Fig. 2b1: Ibid.

2b. Lateralspines of Ab8 shorter than (or absent) than middorsal length of Ab9(picture); or, if with long spines on Ab8, then with dorsal hooks onAb5-7 - 4
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3a(2a). Epiproct as long or longer than paraprocts (Figure3a1); dorsal hook present on Ab2-4 (Figure 3a2); lateral spines ofAb8 less than 0.66x the length of those on Ab9 (Figure 3a3);crenations of lateral lobe deep, as deep as wide, though may not beapparent in early instars (Figure 3a4);- Pantala

Fig.3a1Fig.3a2 Fig.3a3 Fig.3a4
Fig. 3a1:
Pantalahymenea larva (12.5x, dorsalview), 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. Epiproctshorter than paraprocts (picture); dorsal hook absent on Ab2-4(picture); lateral spines of Ab8 about 0.9x the length of those onAb9 (picture); crenations of lateral lobe shallow, much wider thandeep (picture); - Tramea

Fig. a Fig. b Fig. c Fig. d
Fig x-x:
Tramealacerata larva, collectedfrom Radnor Lake, Davidson Co., Tennessee by M. Wright on 10 April1936. Fig a and c taken at 12x, fig b and d taken at 25x.

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

Fig. 4a1Fig. 4a2
Fig. 4a1:
Nannothemisbella larva (3x, dorsalview), from roadside ditch at Juniper Creek, Calhoun Co., Florida,collected on 18 March 1974 by M. J. Westfall, Jr. Specimen loancourtesy of B. Mauffrey, IORI
Fig. 4a3: Ibid, (6x, dorsal view).

4b. Middorsal hooks present or absent; lengthof 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, cappinganterolateral part of head and raised dorsally above contour of headcapsule (picture); abdomen long and tapering to an acute point(picture) - 6

5b
. Eyes occupying about half thelength of head, more broadly rounded and lateral in position, notprotruding above contour of head capsule (picture); body usuallyshort and blunt (picture) - 8
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6a(5a). Distal margin of prementum smooth (crenationsvisible only at magnification 15x, with spinulose setae not innotches between bases), and apical margin of prementum straight oneach side of median line (picture) - Libellula


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

6b. Distalmargin of prementum clearly crenate (crenations clearly visible at5x, spinulose setae within notches of crenations), and apical marginof prementum convex on each side of median line (picture) -7

Fig. a
Fig. a: Plathemislydia larva, 12x dorsal view.Collected from the Maple River, Emmet County, Michigan, on 23 August1953 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-lateralbrown or black ridges on Ab7-9 (picture) - Ladona

7b
. 8-11dorsal premental setae on each side of median line (picture); nomiddorsal hooks on Ab7-8 (picture); Ab7-9 with brown or black,shining, dorsal-lateral ridges (picture) - Plathemis

Fig. a Fig. b
Fig. a-b:
Plathemislydia larva, dorsal view at25x and 12x, respectively. Collected from the Maple River, EmmetCounty, Michigan, on 23 August 1953 by E. J. Kormondy.UMMZODO-0967.

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

8b
.Paraprocts and cerci straight or nearly so (picture); lateral spinesusually present (picture) - 9
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9a(8b). Middorsal hooks absent (picture), or representedonly 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 lateralspines of Ab9 extending farther caudad than tip of epiproct, longerthan middorsal length of Ab9 (picture); dark ridge running mesad frommesoposterior part of eye (picture); antennal segment 6 markedlydarker than segment 5 (picture) - Pachydiplax

10b
. Tipsof lateral spines of Ab9 not extending beyond tip of epiproct, equalto or shorter than middorsal length of Ab9 (picture); no dark ridgerunning mesad from mesoposterior part of eye (picture); antennalsegment 6 not as above (picture) - 11
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11a(11b). Lateral spine ofAb8 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, reachingto or beyond tips of paraprocts and about 2x the middorsal length ofAb9; 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. Lateralspines of Ab9 < 2x the middorsal length of that segment, notextending to tips of paraprocts (picture); dorsal hook present orabsent on segment 8 (picture) -13
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13a.(13b). Middorsal hook on Ab3 (picture); epiproctparaprocts about equal in length (picture) - Leucorrhinia

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