Fasciatus complex. The following four species are among the more difficult Orthopterans of the Dakotas to identify. The short key provided will only work with well marked specimens. In nature, the species are readily distinguished by song. Of the four included species: A. fasciatus and A. allardi are widespread, while A. tinnulus and A. maculatus have only been reported from South Dakota.
A. Wings macropterous, extending to end of abdomen or beyond.
a. Head with occiput and fastigum crossed by five well marked dark stripes. Average number of stridulatory pegs on male tegmen 114.
Allonemobius fasciatus
a.’ Head with dorsal stripes obscure or absent. Average number of stridulatory pegs on male tegmen 194.
Allonemobius allardi
B. Wings micropterous, extending 3/4 length of abdomen or less.
b. Pronotum ‘barrel shaped,’ widest at mid-length.
c. Head with occiput and fastigum crossed by five well marked dark stripes, Ovipositor longer than hind femur.
Allonemobius fasciatus
c.’ Head without stripes, face mottled with a pale ring around each compound eye. Ovipositor as long as hind femur.
Allonemobius maculatus
b.’ Pronotum trapezoidal, gradually widening posteriad.
d. Head with indistinct stripes. General coloration shades of brown to gray brown. Widespread grassland species.
Allonemobius allardi
d.’ Head without dark stripes. General coloration yellow-brown, tending to reddish on dorsum of head and pronotum. Woodland species in SE South Dakota.
Allonemobius tunnulus