Fireflies had always been a part of an Ohio summer, though much reduced in the DDT years. It never crossed my mind that every place didn't have them until I heard the story of a Scottish harpist who came to Oberlin for the Scottish music summer school. SHE had never seen one and was heard to exclaim "Ohhhh! There ARE faeries at the bottom of the garden!" I loved that reaction.
I think Craig Johnson's "New Harmony" captures that feeling of them being a part of life so well:
Evening hillsides, summertime The jars we filled with fireflies...