A medium-size (2.8.3.0 cm wingspan) dull yellow brown moth, without darker markings. The forewing color is slightly darker on the lower half, inside the postmedian line near the apex and in an indistinct band running from the postmedian line through the reniform area. It is also lighter along the distal side of the postmedian line, in particular just below the apex. The reniform is marked by a few grey scales in some specimens, obsolete in others. The hindwing is dull white, lightly dusted with brown scales, especially near the outer margin. Antennae simple, sexes similar.  The related P. spumosum is larger more evenly colored and has more pointed forewings. A key to the species of Plagiomimicus, along with illustrations of both adults and the genitalia of both sexes, is provided in Poole, 1995.