Identification: Key feature of P. fimetaria and P. merdaria is the presence of thoracic markings in the shape of two pairs of spectacles (elongated towards the rear). The markings may be very feint. This species is similar to P. merdaria , differentiated as follows:
P. fimetaria: Eyes large but similarly reniform, not rounded. Third antennal joint rather smaller and darkened on outer side about base of arista; hairs beneath second antennal joint longer; arista with longer pubescence. Scutellum slightly shorter in proportion to width and the pair of strong bristles not quite widely separated. Wings with a less yellow tinge about the veins
These characters are rarely evident in photographs unless a sharp image of the head is obtained.