Coarse-backed Red Paper Wasp

The length of the forewing is 18.0–21.5 mm in the female, 17.0–18.0 mm in the male. The body of the creature is almost entirely rusty red, broken by a number of black to dark brown markings. These markings consist of a usually well developed spot around the eyes, this rarely divided into individual spots around each eye, and often a spot in front of pronotal carina. In some cases there are yellow markings on the propodeal valves and tarsi. Polistes rubiginosus and P. carolina are the only large red-coloured wasp species in the eastern US. P. rubiginosus is, however, extremely similar to P. carolina, and can be found in the same regions; the key morphological difference being the malar area (the "cheek") seen from the side, but this works only for the female wasps. This area and the gena are covered in silvery pubescent hairs. P. rubiginosus is the only Polistes wasp in the P. fuscatus-group to have this characteristic, all other species have this area bare or almost so. Both sexes of P. rubiginosus can also be distinguished from P. carolina by the coarser transverse ridging of the propodeum.

This species is endemic to the eastern United States. It has been recorded from Pennsylvania south to Georgia and west to Kansas, Oklahoma, and Texas. This currently understood distribution largely overlaps with that of P. carolina, apart from absence in Florida. Because this species is very similar to P. carolina, its historical range may have been under-reported.

The ecology is poorly known because of the aforementioned confusion with P. carolina. It is a eusocial insect, building nests in sheltered locations such as in hollow trees, or under wooden platforms and inside storage buildings.