An old folktale states that if a firefly comes into a person's house, the following day there will be one less person in the house. It is not known what it means by saying one less person in the house, but many people take this to mean that a person who resides in the house will die.

Fireflies are also known as lightning bugs. They are nocturnal, luminous beetles. They get their name from the fact that some species as adults emit flashes of light to attract mates, using special light-emitting organs in the abdomen. The flashing and flying pattern that fireflies use is distinct for each species. Many species of lampyrid beetles do not glow as adults, but they all glow as larvae. There are more than 2000 species of firefly, found in temperate and tropical environments around the world.