Cable pretty much got. The males have a smaller less developed gaster, er abdomen. The females do indeed look just like much larger winged workers. I think what you are finding is those few sexuals which did not fly during the flight season. I am still getting sporadic alates of P. rugosus showing up at my house, but the odds of the queens being fertile is about zero. Yesterday I looked at one of the colonies in my yard and noticed about a dozen dead alate queens at the colony entrance. I suspect they are ebing turned out to die so as not to drain colony resources over the winter.