1. Field and House crickets (Gryllinae: Gryllus, Acheta).
A. Tarsi three segmented.
B. Pronotum shiny black or light brown and black, not bristly.
C. Tibial spurs < ½ length of 1st tarsal segment.
D. Body length > 1.5 cm.
A. Pronotum light brown with darker markings.
Acheta domestica
B. Pronotum black.
a. Adults in Spring and early Summer.
Gryllus veletus
a.’ Adults in late Summer and Autumn.
Gryllus pennsylvanicus
2. Tree crickets (Oecanthinae: Oecanthus).
A. Tarsi three segmented.
B. Body coloration pale green.
C. Mouthparts directed forward (prognathus).
A. Scape and pedicel unmarked or each with a single ventral black marking.
a. Scape and pedicel unmarked.
Oecanthus latipennis
a.’ Scape and pedicel with a single black mark each.
b. Scape and pedicel each with a black spot.
Oecanthus fultoni
b.’ Scape with an inwardly hooked black line.
Oecanthus niveus
B. Ventral scape and pedicel each with two black markings.
a. Black marks separated by a distance greater than the width of the inner mark. Outer mark often less intense.
Oecanthus quadripunctatus
a.’ Black markings more or less coalesced, may be separated by 1/3 width of inner black mark.
b. Markings on both scape and pedicel coalesced. On left scape, markings take the form of an ‘'’ in anterio-ventral view (marking of course transposed on right scape).
Oecanthus argentinus
b.’ Markings usually separated by about 1/3 width of inner mark, when coalescent, scape suffused with brownish.
Oecanthus nigricornis
Note: just east of the Dakotas, O. nigricornis has the antennae, tibiae and tarsi largely blackish. Specimens of this type can be found along the eastern edge of our area and there appears to be a complete blend from dark O. nigricornis to O. argentinus. Only the extremes will be separable using this key. Note- species are separable by sound and stridulatory peg numbers.
3. Ground crickets and Bush crickets (Nemobiinae and Trigonidinae).
A. Tarsi three segmented.
B. Pronotum tomentose and bristly.
C. Body length < 1.5 cm.
Note: The key that follows is the most tedious of the website, even though some of the species are quite distinctive even to the unaided eye.
A. Small species, body length < 8 mm. Basal segment of hind tarsus with a single long apical spur, second tarsal segment heart-shaped, ovipositor shorter than hind femur, blade-like, upturned, not enlarged apically. Southeastern SD only.
Anaxipha exigua
B. Length variable. Basal hind tarsal segment with two long spurs, second tarsal segment small, cylindrical, ovipositor with apex enlarged.
a. Two median spurs at apex of ventral hind tibia subequal in length, maxillary and labial palpi white.
Eunemobius carolinus
a.’ Two median spurs at apex of ventral hind tibia of unequal lengths, palpi not white.
b. Ovipositor curved, < 3/4 length of hind femur. Southeastern South Dakota .
c. Face unmarked brownish.
Nemobius palustris
c. Face with contrastingly dark band on lower half.
Nemobius bruneri
b.’ Ovipositor straight, as long or longer than hind femur. Species widespread in the Dakotas.
d. Lower half of face piceus (glossy black) contrasting with gray vertex and frons. Found in sandy areas.
Allonemobius griseus
d.’ Lower half of face not piceous.