Is it Lightning Bugs or Fireflies?

It's the question always asked about in the Summer sitting around the back yard- are they fireflies or lightning bugs.

According to this poll and living in New Jersey we say lightning bug. CLICK HERE for the break down through-out the country and find out who calls the cool Summertime bugs that light up from their behind, a lighting bug or a firefly.

For me, it's always been a lightning bug!

Is it lightning bug or firefly?