This one was surprisingly straightforward to identify. The lack of a sclerite at the base of the lateral hump narrows the field quite a bit, and the other options followed fairly obvious characteristics to Clostoeca, which only has one species, Clostoeca disjuncta.
Described by Frison, T.H. (1942) Studies of North American Plecoptera, With Special Reference to the Fauna of Illinois. Illinois Natural History Survey Bulletin 22, 235–355.