Cantharis

Cantharis, a genus of vesicant Coleoptera or Blister-beetles (q.v.), familiarly represented by the Spanish Fly of Southern Europe (Cantharis or Lytta vesicatoria). Some of the characters are noted under BLISTER-BEETLE. The insects are shaken with gloved hands from the branches of trees (ash, privet, lilac, elder, &c.), the gathering in the south of France taking place in May; they are usually killed in hot vinegar solution and carefully dried. To retain their medicinal vesicant properties they must be kept in stoppered bottles. The blistering principle, or cantharidine, is so powerful that those who gather the insects are apt to suffer, and $\backslash frac\{1\}\{100\}$th of a grain, placed on the lip, will raise blisters. Incautious internal application may cause fatal inflammation. Vinegar, tincture, and plaster of cantharides are used externally for producing blisters. A distilled alcoholic solution of cantharidine is sometimes called Aqua Tofana (q.v.). The insects are usually imported to Britain from Southern Europe or Russia. They rarely occur in England.