One of our favorite books to read after being outside and catching "lightning bugs" (or fireflies as some of you may call them) on a hot July night is "Sam And The Firefly". It's a fun story about an owl named Gus who befriends and helps a trouble-making firefly named Sam.
For some time, I've wanted to do some type of firefly craft (without buying glow in the dark paint) to go along with the book, and finally found inspiration (after reading this Artful Parent post) to make crayon relief fireflies.
I drew several fireflies (pardon my lack of knowledge in the firefly anatomy department) on a piece of heavy weight paper - leaving the lower section of the abdomen (which lights up) blank. I had my daughter color that section later with a white and yellow crayon (the yellow produced the best effect).
She then painted over the fireflies with various shades of watercolor paints and loved watching them "light up" like magic.