In the last week I have seen 2 adult Tiger Swallowtails. This seemed odd to me because, as far as I know Papilio canadensis is a univoltine species (at least up here around Ottawa) and it's flight period should have ended by now. See my earlier post on swallowtail cohorts.
Aside: voltinism is the number of generations a species of butterfly (or other taxa) has in a year. Univoltine species have one generation in a year, bivoltine have 2, mutivoltime have >2, and semivoltine have <1.