The carapace is about 3 millimetres (0.12 in) long, is colored dark brown, and has several rows of white feathery setae.

Their eyes span half the width of their head, both rows slightly procurved.

When alarmed, P. mahannopi joins the femora of its first pair of legs together in front of its head, mimicking a third body segment.

At the same time, they wave the tibiae and metatarsi in the air, mimicking ant antennae.

[2] Its main mimic model seems to be Diacamma, a queenless ant genus belonging to the subfamily Ponerinae.