Sources : Cantharis

Aristotle [ca. 350 BCE] (De animalibus, Book 5, 17.11): The cantharis [is produced] from worms which dwell on the fig tree, apium [pear tree], and pitch tree... - [Cresswell translation, 1887]

Pliny the Elder [1st century CE] (Natural History, Book 8, 28): ...beetles are produced by the maggots of figs and of the pear tree, pine, dog-rose and rose. This poisonous creature brings its remedies with it - the wings have a healing power; but with these removed it is deadly. - [Rackham translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Worms 9.16): Cantarides are worms that live in the tops of the branches of the ash or alder tree; they are generated from the moisture in the leaves of the tree, and grow strong like caterpillars, but they grow wings perfectly, and fly by day. But at night they gather together in one group. These worms, having a green color, glitter with gold under the sun's rays. Around the month of August, they are collected at night as a remedy and killed by being immersed in vinegar. But when dead, pour wine over any member you wish, and place the insect under a wax vessel shaped like a cup, and by its application they raise a burning sensation in the bladder. The bladder, having been pierced in many places with a golden needle or with the point of a straw, expels the evil fluid like a cautery, and its expulsion is only effective for fifteen days as any cautery under a year. - [Badke translation/paraphrase]