I wandered through our field the other day, taking a butterfly survey. One thing I noticed was that there were areas with lots of butterflies and areas with few. Water in the environment seemed to make a pretty big difference–where there was water there were butterflies.
This black swallowtail, Papilio polyxenes, was in the area with sparse numbers of butterflies. It was laying eggs on a wild parsnip plant.
Black swallowtails will be present pretty much all summer and into the fall.