 "P. gallicus" is almost indistinguishable from the European paper wasp, "P. dominula", with which it had long been confused.Nearly every reference to "P. gallicus" prior to 1985 was actually referring to "P. dominula"; due to the great similarity between species, however, many published studies for which no vouchered reference specimens are available cannot be reliably assigned to either species.Most of the literature that pertains to actual "P. gallicus" uses the junior synonym, "P. foederatus", a name which still occasionally appears in the literature despite the known error.