BUT FIRST! If you want them to remain faeries then look away now!Lampyridae is a family in the beetle order Coleoptera, (well done Jenny) members of which are commonly called fireflies, lightning bugs or (ambiguously) "glow worms" due to their conspicuous nocturnal (or, more accurately, crepuscular) use of bioluminescence to attract mates or prey. Fireflies are capable of producing a "cold light" containing no ultraviolet or infrared rays, with a wavelength from 510 to 670 nanometers, pale reddish, yellowish or green in colour, with a lighting efficiency of up to 96%.
There are more than 2000 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.