Polistes semenowi, like most other paper wasps, are typically 0.7-1.0 inches long. Because it is a social parasite, it is adapted for fighting off the host species, and has some morphological distinctions. P. semenowi is known to have larger mandibles and anterior legs than those of related species. It also has a more square-shaped head, which is hypothesized to have evolved from the need for robust muscles to power the larger mandibles. Additionally, there is often a black band in the lower half of the clypeus. This trait in particular distinguishes it from its host species P. dominula. P. semenowi males typically have a more complete coloration of the body than the females, with the colors ranging from yellow to almost white.
