Aquatic Insects of Michigan

by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment
University of Michigan

Libellula (Libellulidae) (King Skimmers) of Michigan - Identification

This group of often distinctively patterned dragonflies are familiar to almost everyone. Widely distributed throughout the Northern Temperate Zone, eight species of Libellula have been found in our state. All eight species of Libellula in Michigan can be found in ponds, small lakes or bays, and quiet river margins. L. pulchella appears to have a preference well-buffered waters in calcareous soils, and avoids peaty waters (Walker and Corbet 1975). L. quadrimaculata, on the other hand, appears to prefer the peaty waters of marshes and bogs. L. semifasciata also is found in forested brooks and ponds, marshy bays and seepage ditches. L. vibrans has recently (Craves 2006) been added to our state list, with adults being netted in southeastern Michigan. In 2013, Libellula auripennis finally appeared in SE Michigan (Nirschl 2013). It is included in the keys below, but it is doubtful that it is a resident species.

Taxonomic references: Needham et al. 2014, Paulson 2011, Tennessen 2019, Walker and Corbet 1975

Adults

1a	a. Basal quarter to third of each hindwing brown or black, this dark area extending to the anal angle of the wings	Libellula luctuosa Burmeister
1b	a. Hindwings with basal dark markings, if present, less extensive, never reaching the anal angle of the wing	2
2a(1b)	a. Wings each with a dark spot at nodus extending backward at least to vein M4	3
	b. Wings often with a distinct dark band posterior to each pterostigma, sometimes extending to wing tip
2b	a. Wings each with dark spot at nodus, if present, not nearly reaching vein M4	4
	b. Wingtips lacking a dark band behind the pterostigma, sometimes dark beyond the pterostigma
3a(2a)	a. Supertriangle of each forewing, and midbasal space of each hindwing, transparent saffron	Libellula semifasciata Burmeister
	b. 1 or 2 bridge crossveins
	c. Wingtips incompletely dark, giving appearance of banding pattern
3b	a. Supertriangle of each forewing, and midbasal space of each hindwing, brown or black	Libellula pulchella Drury
	b. 3 or more bridge crossveins
	c. Wingtips completely dark
4a(2b)	a. Basal dark spot of each hindwing covering the triangle and extending posteriorly to a point about halfway between the base of vein Cu and the anal angle of wing	Libellula quadrimaculata Linnaeus
	b. Forewing without distinct dark basal markings
	c. Lateral carinae of Ab2 shorter than posteroventral carinae
4b	a. Basal dark spot of each hindwing absent, or not reaching the triangle or extending posteriorly to base of vein Cu	5
	b. If a large basal dark spot extends to base of vein Cu or anal angle of hindwing, then large dark basal marking also present in forewing
	c. Lateral carinae of Ab2 longer than posteroventral carinae
5a(4b)	a. Costa yellow or red proximal to nodus	Libellula auripennis Burmeister
	b. Wings without basal dark streaks and with membrane transparent yellow to reddish, at least anteriorly or basally
	c. Pterostigma not bicolored
	also: Mesepisterna with ventrolateral corners brown, concolorous with region immediately posterodorsad
5b	a. Costa black distal to nodus	6
	b,c. Wings usually with basal dark streaks, either with pterostigma bicolored, or with membrane not yellow or orange, or both
6a(5b)	a. Mesepisterna with anteroventral corners brown, concolorous with region immediately posterodorsad	Libellula cyanea Fabricius
	b. Ab3 with posteroventral carina at least half as long as the ventromedial varina
	c. Pterostigma bicolored, pale basally with more than apical third dark brown, about 4x (males) or 5x (females) as long as its greatest width
6b	a. Mesepisterna with anteroventral corners pale, contrasting with the region immediately posterodorsad	7
	b. Ab3 with posteroventral carina at less than half as long as the ventromedial varina
	c. Pterostigma not bicolored
7a(6b)	a. Face white	Libellula vibrans Fabricius
	b. Upper margin of mesepimeron without brown, triangular marking near base of the forewing (marginal ridge itself is brown)
	c. Males with a basal, ventrally directed projection from distal segment of penis, visible anterior to hamules in lateral view, that is nearly straight and pointed apically
7b	a. Face mostly brown or black	Libellula incesta Hagen
	b. Upper margin of mesepimeron with brown, triangular marking near base of forewing
	c. Males with the projection bent posteriorly at apex

Mature Nymphs

1a	a. Dorsal hook absent on Ab8	Libellula pulchella Drury
1b	a. Dorsal hook present on Ab8	2
2a(1b)	a. Palpal setae 5-6	3
	b. Ratio of prementum length : maximum width (distal) usually ≥ 1.0 (except L. cyanea and L. incesta, which have palpal setae 5-6)
2b	a. Palpal setae 7-10 (rarely 6)	6
	b. Ratio of prementum length : maximum width (distal) usually ≤1.0 (except S. semifasciata, 1.03-1.05 which has palpal setae 8-9)
3a(2a)	a. Head width usually >6.0 mm	Libellula vibrans Fabricius
	b. Maximum width of abdomen > 8.0 mm
	c. Total length usually > 25 mm
	d. Majority of middle distal crenations of palp with 5 setae
3b	a. Head width usully <6.0 mm	4
	b. Maximum width of abdomen < 8.0 mm
	c. Total length usually < 25 mm
	d. Majority of middle distal crenations of palp with 4 setae
4a(3b)	a. Prementum length 4.75-5.30 mm, basal width 1.75-2.05 mm	Libellula auripennis Burmeister
	b. Ratio of epiproct length : basal width 1.82-2.04
	c. Abdominal dorsum relatively evenly tan to orange brown, slightly paler medially but on Ab8-9 darker sublaterally
	also: Dorsum of Ab5-9 mostly uniform brown, not obviously mottled
4b	a. Prementum length 3.90-4.55 mm, basal width 1.45-1.70 mm	5
	b. Ratio of epiproct length : basal width 1.82-2.04
	c. Abdominal dorsum mostly brown, usually as dark medially as sublaterally on Ab6-9
5a(4b)	a. Epiproct length 1.80-1.95 mm	Libellula cyanea Fabricius
	b. Ab3 ventral width <6.0 mm
	c. Ab9 posterolateral spine length usually <0.50 mm
5b	a. Epiproct length 1.95-2.15 mm	Libellula incesta Hagen
	b. Ab3 ventral width usually >6.0 mm
	c. Ab9 posterolateral spine length usually >0.50 mm
6a(2b)	a. Length of cercus 1.20-1.50 mm, and >3.5x length of Ab9 posterolateral spine	Libellula quadrimaculata Linnaeus
	b. Ab9 posterolateral spine length 0.24-0.32 mm
	c. Ab3 with distinct middorsal hook, length 0.08-0.20 mm
6b	a. Length of cercus 0.70-1.05 mm, and <3.0x length of Ab9 posterolateral spine	7
	b. Ab9 posterolateral spine length 0.32-0.48 mm
	c. Ab3 with middorsal hook absent or indistinct, length <0.10 mm
7a(5b)	a. Premental setae 27-29	Libellula semifasciata Burmeister
	b. Ratio of prementum length : maximum width 1.03-1.05, ratio of prementum length : basal width 2.80-3.00
	c. Femora with banding indistinct, sometimes with faint preapical brown band
7b	a. Premental setae 19-20	Libellula luctuosa Burmeister
	b. Ratio of prementum length : maximum width 0.90-0.99, ratio of prementum length : basal width 2.53-2.75
	c. Femora with distinct brown basal and preapical brown bands

Craves JA. 2006. First Michigan specimens of Libellula vibrans Fabricius (Odonata: Libellulidae). Great Lakes Entomologist 39(1-2): 91-93.
Musser RJ. 1962. Dragonfly nymphs of Utah (Odonata: Anisoptera). University of Utah Biological Series 12(6):1-66.
Needham JG, Westfall MJ, May ML. 2014. Dragonflies of North America, Third Edition. Scientific Publishers, Gainesville, Florida, USA. xiv + 657 p.
Nirschl R. 2013. First record for Libellula auripennis (Golden-winged Skimmer) in Michigan. Argia 25(3):18
Paulson D. 2011. Dragonflies and damselflies of the East. Princeton Field Guides. Princeton University Press, Pinceton, New Jersey, USA. 538 p.
Tennessen KJ. 2019. Dragonfly nymphs of North America: An Identification Guide. Springer International Publishing, Cham, Switzerland: xiv + 620 p.
Walker EM, Corbet JS. 1975. The Odonata of Canada and Alaska, Vol. 3. University of Toronto Press: Toronto, Ontario. xvi + 308.

Page created: July 17, 1998 - Last updated: April 22, 2020 (EB)