They would always appear in the same spot in our backyard, near a small hill around the base of an old telephone pole. Catching them was easier than you might think. One simply had to wait for the little insect to signal with its glowing abdomen and scoop it up. Where I live now in suburbia I rarely see them in great enough numbers to do this, but when I was a child, the night air was full of them.
I'd take my jar inside and inspect the bug under some light. What a strange creature lived there on the other side of my fingers and a few millimeters of glass.
Then I'd sit the jar next to my bed and go to sleep, but with one eye open to watch my little prisoner. Sometimes I'd see it glowing there, but never so brilliantly as outside.
In the morning I'd find the firefly lifeless on the bottom of the jar. I don't think one ever made it through the night. There's probably a metaphor in that, if one cared to think a little more about it.