This species is difficult to distinguish from P. rufiventris.

P. subventa has 2 pairs of pre-sutural acrostichal bristles and 2 posterior bristles on the mid-tibia. Tip of scutellum is yellow-orange.

P. rufiventris has 1 pair of acrostichal bristles and 3 posterior bristles on the mid-tibia.  Scutellum is yellow-orange.