I thnk that if you want fireflies indoors, you should build a firefly hive, and inch closer and closer to your house, but still make sure that there are still "fireflies nearby." Repeat until you get where you want.
AwesomeC2K is right. I had indoor fireflies. Just open a jar as far as you can possibly can from the hive. Then move as far away as you can again & open another. Repeat until you have indoor fireflies. See? Not as dense as I would like, but they're in there.
I would love to have a lot more of them in the house. It would be lovely if we could plant a firefly hive inside like a fireplace.