Cantharidæ — Blister-flies
Many species of this family of insect possess strong vesicating powers, and are employed externally in medicine to produce blisters, and internally as a powerful stimulant. Taken internally, Pliny considered them a poison, and mentions the following instance of their causing death: Cossinus, a Roman of the Equestrian order, well known for his intimate friendship with the Emperor Nero, being attacked with lichen, that prince sent to Egypt for a physician to cure him; who recommended a potion prepared from Cantharides, and the patient was killed in consequence.192 But there is no doubt, however, Pliny adds, that applied externally they are useful, in combination with juice of Taminian grapes, and the suet of a sheep or she-goat. They are extremely efficacious, too, continues Pliny, for the cure of leprosy and lichens; and act as an emmenagogue and diuretic, for which last reason Hippocrates used to prescribe them for dropsy.193
The vesicatory principle of the Blister-fly is called Cantharidine, and has been ascertained by experiment to reside more particularly in the wings than in other parts of the body. Our officinal insect is the Cantharis vesicatoria; and since the principal supply is from Spain, we call them commonly Spanish-flies. In Italy, the Mylabris cichorii, a native of the south of Europe, is used; and the M. pustulata, a native of China, is used by the Chinese, who also export it to Brazil, where it is the only species employed. In India also a species of Meloe is used,194 possessing all the properties of the Spanish-fly.
At one time in Germany, the genus Meloe—Oil-beetles (so called from their emitting from the joints of the legs an oily yellowish liquor, when alarmed)—were extolled as a specific against hydrophobia; and the oil which is expressed from them is used in Sweden, with great success, in the cure of rheumatism, by anointing the affected part.195 Dr. James thus enumerates the medicinal virtues of these insects: “The Oil-beetle (Scarabæus unctuosus of Schroder) is much of the nature of Cantharides, forces urine and blood, and is of extraordinary efficacy against the bite of a mad dog. Taken in powder, it cures the vari, or wandering gout, as we are assured by Wierus. The liquor is, by some, esteemed of efficacy in wounds; it is an ingredient also in plaisters for the pestilential bubo and carbuncle, and in antidotes; an oil is prepared by infusion of the living animals in common oil, which some use instead of oil of Scorpions.”196 In some parts of Spain, they are mingled with the Cantharides, for the same purposes as these latter insects. Farriers also employed, in some cases, oil in which these insects had been macerated.197
Pliny tells us that Cato of Utica was one time reproached for selling poison, because when disposing of a royal property by auction, he sold a quantity of Cantharides, at the price of sixty thousand sesterces.198
The natives of Guiana and Jamaica make ear-rings and other ornaments of the elytra, or wing-coverings, of the Cantharis maxima; the brilliant metallic colors of which beetles, says Sloane, sparkle with an extraordinary lustre, when worn by the Indians dancing in the sun.199
Zoroaster says, that “Cantharides” will not hurt the vines, if you macerate some in oil, and apply it to the whetstone on which you are going to set your pruning-knives.200
Cantharides are comparatively rare in Germany; yet we are told in the German Ephemerides, says Brookes, that in June, 1667, there were found about the town of Heldeshiem, such a great number of them, that they covered all the willow-trees. Likewise that in May, 1685, when the sky was serene and the weather mild, a great number of Cantharides were seen to settle upon a privet-tree, and devour all the leaves; but they did not meddle with the flowers. We are also told that the country people expect the return of these insects every seven years. It is very certain, adds Brookes, that such a number of these insects have been together in the air, that they appeared like swarms of bees; and that they have so disagreeable smell, that it may be perceived a great way off, especially about sunset, though they are not seen at that time. This bad smell is a guide for those who make it their business to catch them.201