Pollination could have been accomplished by any appropriate pollinator (like a bumblebee or honeybee for these plants). If you don't see a fruit starting to grow a couple of days after the flower is spent, then it usually means that it wasn't pollinated.
Also, I hate to be a downer, but it is pretty late in the season to be pollinating and pushing for fruit. Especially in your case since your in PA. Remember that P. parviflora is an annual. The fruit need at least 50 days to mature, and by that time it'll be November and pretty cold. In other words, your plants will be long gone. This is assuming you are growing them outside. I guess it is possible to move the plants into a heated greenhouse and continue growing them through the winter...
My plants are already looking dead-ish. I had another plentiful harvest this year and will be having a seed offer early next year if you need some.