Sad fact: They are disappearing. Nobody knows for sure why, but most researchers blame two main factors: development and light pollution.
The Lampyridae are a family of insects in the beetle order Coleoptera. They are winged beetles, commonly called fireflies or lightning bugs for their conspicuous use of bioluminescence during twilight to attract mates or prey.
Fireflies produce a "cold light", with no infrared or ultraviolet frequencies. This chemically produced light from the lower abdomen may be yellow, green, or pale red.
About 2,000 species of fireflies are found in temperate and tropical climates. Many are in marshes or in wet, wooded areas where their larvae have abundant sources of food. Their larvae emit light and often are called "glowworms" in Eurasia and elsewhere. In the Americas, "glow worm" also refers to the related Phengodidae.
In many species, both male and female fireflies have the ability to fly, but in some species, the females are flightless.
To learn just about everything there is to know of these amazing creatures go Firefly.org.