The bugs that come out at night when it’s hot and humid that glow from the rear…what do you call that bug? Did you say firefly or lightning bug? Your answer might have something to do with where you grew up. According to a study at NC State University the exclusive use of ‘firefly’ seems to be a Western United States thing. If you say ‘lightning bug’, you most likely grew up East of the Rockies. So, what do you call it?