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
Back to previous couplet
(1)
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.3a1
Fig.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.
Back to previous couplet
(2); Back to beginning of key
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
Back to previous
couplet (2); Back to beginning of key
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
Back to previous
couplet (4); Back to beginning of key
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.
Back to previous couplet
(5); Back to beginning of key
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.
Back to previous couplet
(6); Back to beginning of key
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
Back to previous
couplet (5); Back to beginning of key
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
Back to previous
couplet (8); Back to beginning of key
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
Back to previous
couplet (9); Back to beginning of key
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
Back to previous
couplet (10); Back to beginning of key
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
Back to previous couplet
(9); Back to beginning of key
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
Back to previous
couplet (12); Back to beginning of key