Sources : Fly
Pliny the Elder [1st century CE] (Natural History, Book11, 42, 28): Some creatures are generated also by the opposite natural element. Thus in the copper foundries of Cyprus even in the middle of the fire there flies a creature with wings and four legs, of the size of a rather large fly; it is called the pyrallis, or by some the pyrotocon. As long as it is in the fire it lives, but when it leaves it on a rather long flight it dies off. - [Rackham translation]
Isidore of Seville [7th century CE] (Etymologies, Book 12, 8:11): The word for fly (musca) comes from Greek, as does mouse (mus). These animals, just like bees, when drowned in water, sometimes revive after an hour has elapsed. - [Barney, Lewis, et. al. translation]
Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Worms 9.29-30): [Worms 9.29] As the Liber rerum says, a fly flies recklessly. It loves the light and does not know how to walk in the dark. It lends itself more willingly to the heat. It is wet inside; it craves blood. It infests every animal, and especially man. Wherever it touches freshly slaughtered meat, worms immediately follow it, which corrupt the infected meat, and this especially in the dog days [summer]. It avoids salted and rough things; it likes to contaminate white and clean things, and the stain of this impurity cannot be washed away as long as the circle of the year rolls around. As the Experimentator says, a fly immersed in water and drowned revives. Dung is generated from corruption. In flying round it makes a noise, and this from the air which is stirred up between the wings. It has a beak like a hollow reed. It sharpens its wings with its hind legs, and with its forelegs its beak and head. Pliny: They hide in the winter after being extinguished very similarly. But in the month of August they make a violent noise. They eat worms, from which flies come; and these worms are hard and black. A fly lacks memory. [Worms 9.30] [Thomas has misread Pliny to create the "flies of Cyprus'".] There is a kind of fly in the region of Cyprus, four-legged, as Pliny says, and with wings, much larger than our flies. They are called piralle from pyr, which is fire. For they remain in the furnaces and fly with impunity in the midst of the fires. And this is a wonderful thing: as long as it is in the fire it lives; but when it has flown a little farther outside, then it dies. - [Badke translation/paraphrase]