Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Worms 9.46): A tappula is a worm supported by four legs. This worm, having feet, walks boldly upon the waters, and is not afraid of the swirling of the waters. It lives equally on land and in water. It indeed runs very quickly on land, and yet more so on water, so that in a short time it can cover long distances of water in a rush; it stops, however, in it charge across the waters, and recovers its fatigued strength. Therefore it is very wonderful in this worm, that although it runs on the water, it remains dry with its body and feet. If you keep the worm itself forcefully under the waves for a long time, it does not get wet or die, but as it returns to the surface, it is dry and ready to act with speed, usually undisturbed. - [Badke translation/paraphrase]

Albertus Magnus [ca. 1200-1280 CE] (De animalibus, Book 2, 41): Tappula is an insect that runs on four feet across the surface of bodies of water, and is an aquatic spider. It also walks on dry land and, when held under water, does not drown or get wet. It seems to walk on water with dry footsteps and covers a considerable distance over the water’s surface with great rapidity. When it becomes tired, it sometimes stands still on the water and revives its energies. - [Scanlan]