A small, short lived, cold dwelling insect. Its body measures between 1 and 1.5 inches. It is found in Northern Paorr, Manenlande, and Titania.
As an adult, the swarm fly has no mouth parts and, as such, cannot eat. In its larval stage, it subsists on a diet of decaying wood, leaves, and other plant matter.
The adult swarm fly typically emerges during the final thaws of the season and are generally considered a sign that warmer weather is coming. During this time, they can live in swarms of 500 or more, hence the name. However, they are still a fairly common occurrence during the first half of the year. Because the air and the ground are of significantly different temperature during the big thaws, there are frequent fogs. With the luminescence of the flies and the fog, it appears that small balls of light a "magically" floating through the forest they resemble a will o'wisp. Due to this resemblance, they have the nickname "whispy".
The swarm fly uses its bioluminescence to attract mates. Both males and females glow and have been observed producing different patterns. The bioluminescent activity ends for the females once they lay their eggs, while the males will continue to search for additional mates until they die. Since the adults cannot eat, and the physical requirements of bioluminescence, the swarm fly usually only lives for 24 hours after emerging. In its larval stage, it grows fairly slowly, taking the remainder of the fair weather to go through its development. Once the first frost arrives, the larva buries itself and begins to pupate. In its pupal stage, it will be completely frozen. Once the first thaws arrive, the pupa continues its metamorphosis.