Fine-backed Red Paper Wasp

Both sexes of P. carolina are about 25–32 mm (0.98–1.26 in) long with black wings of lengths ranging from 15–25 mm (0.59–0.98 in). P. carolina is often confused with P. rubiginosus due to its strikingly similar reddish-brown coloring. Females can be separated by the bare genae of P. carolina in contrast to the silvery pubescence on the genae P. rubiginosus. Both sexes can also be differentiated by the coarser transverse ridging of the propodeum of P. rubiginosus when compared with P. carolina. Additionally, female P. carolina specimens have mostly bare malar spaces (the distance between the lower eye orbit and the mouth).

Sexual dimorphism. Females of Polistes carolina are usually completely ferruginous (rust in color) with the possibility of black markings forming spots around their eyes, lines on the dorsal surface of the scape, narrow lateral stripes on their scuta, or an incomplete median stripe on their propodea. Bands on sternum 2 or terga 3 and 4 can also be present. Additional very restricted yellow markings can be observed on mandibles, clypei, inner orbits, terga 1, the outer surfaces of the tibiae, and tarsi. Females also have more triangular faces with shorter antennae. Males often have more developed black or brown markings such as spots on the midfemur and sterna. Yellow markings vary, but have been reported on the face and sterna 1 through 4. …

P. carolina is most commonly found in the eastern United States (along with another "red paper wasp", Polistes rubiginosus) from Nebraska to Texas and along the Atlantic coast from New York to Florida. It has also been recorded as an adventitious species in Ontario, Canada, and was introduced to Bermuda. It prefers to nest in protected areas such as hollow trees and is often observed in woodlands. However, given the opportunity, it will also construct nests near humans, such as the undersides of roofs.

In P. carolina, several foundresses mate; however, each foundress only mates once. The absence of early males in P. carolina is unique when compared to other Polistes species. This lack of early males, however, indicates that female workers do not become inseminated queens in this species as is common in other wasp species.