Phrynotettix robustus occultus Rehn, J.A.G. & H.J. Grant Jr., 1959

Rehn, J. A. G. & H. J. Grant Jr. 1959. A review of the Romaleinae (Orthoptera: Acrididae) found in America north of Mexico. Proceedings of the Academy of Natural Sciences, Philadelphia (Proc. Acad. Nat. Sci. Philad. ) 111:109-271