Even though further west than the others, it has the earmarks of a "Northern", but not quite, and it was flying in September, which in theory a Northern should not be (in theory they are single-brooded with a flight in spring / early summer - emphasis on "in theory"). There is something found from the northern Plains to New England that flies at least twice per year, has very dark borders on the wings above in males, and which may be a distinct species (or maybe it's the real P. cocyta and the larger single-brooded thing is something else? It isn't really sorted out yet, with people from different regions treating them differently.