Aquatic Insects of Michigan

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

[under construction]

The key below for adult Orthoptera that are considered semi-aquatic is adapted from the Bland's (2003) outstanding work on the Orthoptera of Michigan. The user is referred to this volume for a complete diagnosis (and excellent photos and illustrations) for each species.

1a	Pronotum prolonged posteriorly, reaching at least to tip of abdomen	Tetrigidae
1b	Pronotum not prolonged posteriorly	2
2a(1b)	Front legs strongly flattened, adapted for digging	3
2b	Front legs not adapted for digging	4
3a(2a)	Body length > 1 cm; all tarsi 3-segmented	Gryllotalpidae, Neocurtilla hexadactyla hexadactyla
3b	Body length <1 cm; all tarsi 0- to 2-segmented	Tridactylidae
4a(2b)	Antennae <2/3 body length	Acrididae
4b	Antennae > 2/3 body length	5
5a(4b)	a. Dorsum of body strongly arched in profile	Rhaphidophoridae, Ceuthophilus meridionalis
	b. Pronotum morphology resembles that of abdominal terga
5b	a. Dorsum of body relatively straight in profile	6
	b. Pronotum morphology clearly different from that of abdominal terga
6a(5b)	a. Tarsi 4-segmented; wings held roof-like in cross-section	Tettigoniidae
	b. Overall color typically green, sometimes brown
	c. Male cerci <1/4 length of hind femora
	d. Ovipositor commonly shaped like a straight or strongly curved sword
6b	a. Tarsi 3-segmented; wings held flat over back in cross-section	Gryllidae
	b. Overall color often gray to black, reddish brown, pale tan to straw color, or dull greenish brown
	c. Male cerci > 1/4 length of hind femora
	d. Ovipositor in most species straight and needlelike (strongly curved in Anaxipha exigua)

ACRIDIDAE (Grasshoppers)

1a	Prosternum with prominent spine	2
1b	Prosternum without prominent spine	8
2a(1b)	Mesosternal lobes longer than their width	Schistocerca Stål, 3
2b	Mesosternal lobes as wide as or wider than their length	4
3a(2b)	a. Antennal length nearly equal to combined length of head and pronotum	Schistocerca americana (Drury)
	b. Tegmina with large dark blotches
	c. Body with a pale longitudinal dorsal stripe
	d. Male cerci narrowed toward apex
3b	a. Antennae at least the length of (female) or much longer (male) than the combined length of head and pronotum	Schistocerca alutacea (Harris)
	b. Tegmina with small weak blotches or uniformly colored
	c. Body with or without pale yellow, longitudinal dorsal stripe
	d. Male cerci squarish, slightly narrowed toward apex or parallel-sided
	also: Dorsal region at front of eyes (fastigium) narrow; apical margin of male's cerci deeply emarginate; female with upper surface of dorsal ovipositor valve shallowly curved
4a(2b)	Wingless	Booneacris glacialis canadensis
4b	Winged	5
5a(4b)	Face slanted, forming about a 60-degree angle with dorsum of pronotum in profile	Paroxya hoosieri
	also: color of legs, especially hind tibiae, greenish yellow; cerci spatulate, narrower at middle, expanded distally to truncate or weakly emarginate apex
5b	Face nearly vertical, forming 80- to 90-degree angle with dorsum of pronotum in profile	6
6a(5b)	a. Ventral and inner surfaces of hind femora orange-red to scarlet	Appalachia arcana
	b. Hind tibiae greenish yellow or greenish brown
	also: Male's cerci conical, not twisted; ovipositor valves lanceolate in dorsal view, gradually tapering to a broadly acute or obtuse apex
6b	Hind femora and tibiae not in above combination (if hind femora red ventrally, then tibiae also red)	Melanoplus, 7 (males only)
7a(6b)	Hind tibiae greenish	Melanoplus gracilis
	also: Hind femora without crossbands on outer face; cerci as in figure (pending)
7b	Hind tibiae not greenish	Melanoplus borealis borealis
	also: Tegmina surpassing posterior margin of 5th abdominal segment; furculae large, about 1/2 length of supra-anal plate; subgenital plate wider than tall in posterior view; cerci narrow slightly beyond middle, distal third curves upward
8a(1b)	a. Face slanting backwards in profile, sometimes forming an acute angle with dorsum	9
	b. Hind wings colorless in most species
8b	a. Face rounded in profile	Trimerotropis verruculata verruculata
	b. Hind wings very pale yellow to clear yellow proximally
	also: Median carina of pronotum cut by 2 sulci, posterior one usually more distinct; antennae filiform; hind tibiae dull yellowish; overall color dark gray-brown to blackish; apex of hind wing dark
9a(8a)	Lateral carinae of pronotum straight and nearly parallel in dorsal view	10
9b	Lateral carinae of pronotum distinctly incurved at middle and divergent posteriorly	11
10a(9b)	Basal segments of antennae not strongly flattened and only slightly broader than middle segments	Dichromorpha viridis
10b	Basal segments of antennae strongly flattened (ensiform) and distinctly broader than middle segments	Metaleptea brevicornis
	also: Tegmina surpassing tip of abdomen
11a(9b)	a.Ventral edge of hind femora brownish red	12
	b. Hind tibiae dark yellow, sometimes with dark bands
11b	a. Ventral edge of hind femora not brownish red	Chorthippus curtipennis curtipennis
	b. Tegmina and hind femora yellowish to brown, knees of hind femora often dull black
	also: Tegmina unmarked; overall body color greenish yellow to brown; lateral foveolae narrow and rectangular, usually conspicuous, visible from above
12a(11a)	a. Tegmina unmarked	Stethophyma gracile
	b. Lateral carinae cut by 1 or 2 sulci
12b	a. Tegmina with longitudinal white streak along anterior margin above base of legs	Stethophyma lineatum
	b. Lateral carinae cut by 3 sulci

TETRIGIDAE (Pygmy Grasshoppers)

1a	a. Antennae with > 15 segments	2
	b. Front femora with broad, shallow, longitudinal groove or channel dorsally
1a	a. Antennae with <15 segments	3
	b. Front femora without a groove or channel but with a distinct longitudinal ridge dorsally
2a(1a)	Anterior margin of pronotum with distinct acute median point	Tettigidea armata armata
2b	Anterior margin of pronotum without distinct acute median point, margin is obtuse-angulate	Tettigidea lateralis lateralis
3a(1b)	a. Fastigium of vertex slightly or not extended in front of eyes in profile	Paratettix cucullatus
	b. Middle femora strongly lobed on ventral margin
3b	a. Fastigium of vertex greatly extended in front of eyes in profile	4
	b. Middle femora weakly or not lobed on ventral margin
4a(3b)	Median carina of vertex not extended beyond anterior margin of fastigium in dorsal view	Tetrix subulata
	also: Facial profile weakly or not emarginate in front of eyes (above antennae); middle femur 3.8-4.7x as long as broad
4b	Median carina extended beyond anterior margin of fastigium in dorsal view	Tetrix arenosa angusta
	also: Anterior margin of fastigium truncate in dorsal view; pronotum relatively flat in cross-section

RHAPHIDOPHORIDAE (Cave and Camel Crickets)

One species of Rhaphidophoridae - Ceuthophilus meridionalis Scudder - in Michigan is found around semi-aquatic habitats, such as debris of moist forests, floodplains, and edges of lakes and streams (Bland 2003). Males are characterized by: Thoracic terga shiny, with many distinct pale blotches; spurs of hind tibiae with one distinct ridge dorsally, and dorsal spines not darkened at base; Ab8 tergum not strongly extended posteriorly and not concealing the Ab9 tergum; Ab9 tergum truncate and solid, distinctly produced beyond the posterior edge of Ab8 tergum, and extended beyond the base of the cerci; entire length of subgenital plate usually divided vertically by a median sulcus; subgenital plate as high
as wide and shallowly emarginate, upper part of lobes narrow and project slightly. Females have dorsal spines of hind tibiae pale or slightly darkened at base; ventral ridge in proximal area of hind femora with <18 small teeth; and dorsum with broad yellowish orange median stripe, dark region on each side
of stripe.

GRYLLIDAE (Crickets)

1a	a. Hind tibiae with 3 pairs of long spines in sockets (excluding apical spines)	Anaxipha exigua (Say)
	b. Brushlike pad on the ventral side of the 2nd tarsal segment of the hind tarsi
	c. Ovipositor flattened laterally and curved upward
1b	a. Hind tibiae with > 3 pairs of long spines in sockets (excluding apical spines)	2
	b. 2nd tarsal segment of hind tarsi without brushlike pad
	c. Ovipositor needlelike, straight or gently curved, not flattened laterally
2a(1b)	a. Paired distoventral spurs of hind tibiae approximately equal in length	3
	b. Ovipositor < 6 mm long, gently curved upward
2b	a. Paired distoventral spurs of hind tibiae distinctly unequal in length	4
	b. Ovipositor < 4 mm long and gently curved upward or > 4 mm long and straight
3a(2a)	a. Ovipositor > 4.5 mm long	Eunemobius melodius (Thomas and Alexander)
	b. Stridulatory file on ventral side of male's tegmen near base has > 100 teeth
3b	a. Ovipositor < 3.5 mm long	Eunemobius carolinus carolinus(Scudder)
	b. Stridulatory file on ventral side of male's tegmen near base has <75 teeth
4a(2b)	a. Body < 7 mm long, generally unmarked above	Neonemobius palustris palustris
	b. Ovipositor <4 mm long, shorter than hind femur, gently curved upward
4b	a. Body usually > 7 mm long, commonly with dorsal spots or lines	5
	b. Ovipositor > 4 mm long, longer than hind femur, straight
	also: Tegmina short or long, not truncate; hind wings usually present; body reddish brown to black, with distinct or indistinct dorsolongitudinal stripes on head and pronotum
5a(4b)	a. Pronotum barrel-shaped, anterior margin as wide as posterior margin	Allonemobius fasciatus fasciatus
	b. Dorsal surface of head and pronotum with longitudinal dark and pale stripes
5b	a. Pronotum not barrel-shaped, anterior margin distinctly narrower than posterior margin	Allonemobius allardi (Alexander and Thomas)
	b. Dorsal surface of head and pronotum with indistinct to moderately distinct longitudinal stripes

GRYLLOTALPIDAE (Mole Crickets)

One Michigan species of mole crickets - Neocurtilla hexadactyla hexadactyla - is associated with sandy and muddy soils along ponds, streams, and marshes. This species is differentiated from other mole crickets by having the front tibiae with 4 spiny dactyls (claws), and the hind tibiae without spines on distal half of inner face, apex with 8 spines.

TRIDACTYLIDAE (Pygmy Mole Grasshoppers)

1a	a. Body usually > 5.5 mm	Neotridactylus apicialis (Say)
	b. Prosternum with conical process
	c. Tarsus of hind leg similar in length to long pair of apical spurs on hind tibiae
1b	a. Body usually <5.5 mm	2
	b. Prosternum without conical process
	c. Tarsus of hind leg vestigial or absent
2a(1b)	Antennae of male 11-segmented, female 12-segmented	Ellipes gurneyi Günther
2b	Antennae of male and female 10-segmented	Ellipes minutus Scudder

TETTIGONIIDAE (Katydids)

1a	a. Dorsum of head broadly rounding into face in profile or, if slightly rounded, then tegmina are distinctly leaflike	Amblycorypha oblongifolia
	also: Overall coloration green; tegmina leaf-like but oblong-oval and well-developed, 3x or more as long as greatest width, and much longer than pronotum; 6 to 12 teeth on inner edge of hind femora; fore and middle tibiae flat or grooved dorsally; ovipositor long, gradually curved, apex rounded, large teeth at and below apex; costal area without extensive cross-veins; wing and body outline relatively narrow in dorsal view; prosternal spines absent
1b	Dorsum of head flatly rounded into face or angulate in profile	2
2a(1b)	Dorsum of head approximating a right angle with face in profile	Scudderia texensis
	also: Dorsolateral margin of tegmina unstriped; males: supra-anal plate not broadly triangular, apex with notch very broad, with median rounded projection, outer lobes tapering to narrow point and appearing laterally compressed with elongate curved median process that is notched or forked at apex; female: Ovipositor bent abruptly upward, < 1.5 times as long as pronotum; ovipositor broader at base than at middle; tegmina 5-5.5x as long as greatest width
2b	Dorsum of head forming an acute angle with face in profile	3
3a(2b)	Vertex of head extended into a cone (fastigium) of various shapes beyond basal antennal	Neoconocephalus lyristes
	also: Cone distinctly longer than wide, narrowing from base to apex; underside of cone mostly or entirely black; sides of cone straight or slightly concave, cone narrowly rounded apically; tegmina 4.2 to 4.7 times longer than greatest width; ovipositor does not extend beyond tegmina
3b	Vertex of head not extended into a cone beyond basal antennal segment	4
4a(3b)	a. Body small and slender, usually < 17mm long excluding ovipositor	5
	b.Tegmina usually not surpassing end of abdomen, if surpassed, then hind wings extend beyond tegmina
	c. Spines between base of front legs very short or absent
	d. Ovipositor nearly straight
4b	a. Body robust, usually > 17mm long	8
	b. Tegmina surpassing both abdomen and hind wings
	c. Spines between base of front legs long, cylindrical
	d. Ovipositor usually curved upwards
5a(4a)	Sides of abdomen shining black or brownish black	Conocephalus nigropleurum
	also: Male's cerci swollen near base of smooth tooth, apex of cerci slightly concave
5b	Sides of abdomen green or brownish	6
6a(5b)	a. Lower outer edge of hind femora with 1 to 5 small spines	Conocephalus attenuatus
	b. Tooth of male's cerci near base of cerci short, narrow
	c. Ovipositor about twice body length
6b	a. Lower outer edge of hind femora without small spines	7
	b. Tooth of male's cerci not near base of cerci, relatively long, and broad or narrow
	c. Ovipositor less than twice body length
7a(6b)	Hindwings and tegmina surpassing end of abdomen; male's cerci with stout tooth	Conocephalus fasciatus
7b	Tegmina and wings not surpassing end of abdomen	Conocephalus brevipennis brevipennis (Scudder)
	also: Paired prosternal spines present; more than 1 pair of apical spurs on hind tibiae; tooth of male's cerci not beyond middle of cerci; male's cerci beyond (distal to) tooth with inner (dorsolateral) surface concave in cross-section; female's ovipositor £body length, upper margin of ovipositor nearly straight
8a(4b)	Hind tibiae blackish	Orchelimum nigripes Scudder
8b	Hind tibiae not blackish	9
9a(8b)	Male's cerci with portion beyond (distal to) tooth equal to or shorter than basal portion	Orchelimum gladiator Bruner
	also: Posterior lateral sinus of pronotal lobes poorly developed; tooth of male's cercus slender, > 1/2 length of cercus
9b	Male's cerci with portion beyond tooth longer than basal portion	10
10a(9b)	a. Lateroventral margin of distal half of hind femora with 3 to 4 spines	Orchelimum volantum McNeill
	b. Male's cerci pointed apically
10b	a. Lateroventral margin of distal half of hind femora without spines	11
	b. Male's cerci bluntly rounded apically
11a	Males	12
11b	Females	13
12(11b)	Face with median red-brown stripe	Orchelimum concinnumScudder
12b	Face without median red-brown stripe (may be finely dotted	Orchelimum campestre Blatchley
13a(11b)	Ovipositor 1/2-2/3 length of hind femur	Orchelimum gladiator Bruner
13b	Ovipositor <1/2 length of hind femur	14
14a(13b)	Face with median red-brown stripe	Orchelimum concinnum Scudder
14b	Face without median red-brown stripe (may be finely dotted)	Orchelimum campestre Blatchley

Bland RG. 2003. The Orthoptera of Michigan : biology, keys, and descriptions of grasshoppers, katydids, and crickets. Michigan State University Extension: East Lansing, Michigan. 220 p.