Length to 29 mm (Hyperia macrocephala 1). Head subequal to first two pereonites combined. CX IV of large mature specimens pointed, projecting laterally. P III-IV with numerous short (but not uniform) setae on ART 5 and 6. P V-VII naked, short cluster of setae possible only on anterodistal margins of ART 2 of P V and VII. Epimeral plates with sharply pointed posterodistal corners, posterior margin of epimera III strongly convex. UR fairly slender. Telson moderately short.