The forewing post-medial line in Pericyma glaucinans is incurved beyond cell, and then oblique to inner margin. In Pericyma umbrina, the forewing post-medial line is incurved beyond cell, and then sinuous to inner margin. In Pericyma glaucinans, the HW postmedial begins near apex and is straight and oblique towards inner margin (post-medial line is sinuous in umbrina). In Pericyma albidens, the postmedial line is more or less straight, with a small kink at v.4. In Pericyma albidens, the medial black line, curves in to costa, while in Pericyma glaucinans, it is largely parallel to the postmedial.