Helpful page from Bugguide – with into on gender differences, instar differences, color variation.

Chloealtis conspersa

Chortophaga viridifasciata – females usually green; males usually brown; overwinters as nymph, adults in spring
brown male

green female

Dichromorpha viridis – females brown or green; males green on top, brown on sides or light brown on top, dark brown on sides
female

male

Dissosteira carolina

Encoptolophus sordidus

Melanoplus bivittatus

Melanoplus confusus – male and female similar; adults in early summer

Melanoplus dawsoni – short wings; open areas and reconstructed prairies in western part of state

Melanoplus femurrubrum – common; red tibiae, long wings

Melanoplus keeleri

Melanoplus sanguinipes

Melanoplus walshii

Opeia obscura

Orphulella pelidna

Orphulella speciosa

Phoetaliotes nebrascensis

Schistocerca alutacea

Sparagemon bolli