Lampyridae is a family of insects in the beetle order Coleoptera. They are winged beetles, and commonly called fireflies or lightning bugs for their conspicuous crepuscular use of bioluminescence to attract mates or prey. Fireflies are capable of producing a "cold light", containing no ultraviolet or infrared rays. This chemically-produced light, emitted from the lower abdomen, may be yellow, green, or pale red in colour, and has a wavelength from 510 to 670 nanometers.
There are more than 2,000 species of firefly found in temperate and tropical environments around the world. Many species can be found in marshes or in wet, wooded areas where their larvae have abundant sources of food. These larvae can also emit light and are often called "glowworms", particularly in Eurasia. In the Americas, "glow worm" also refers to the related Phengodidae.