Spanish fly

Spanish fly (usually uncountable, plural Spanish flies)

1. (uncountable) A supposed aphrodisiac extracted from the beetle Lytta vesicatoria; cantharidin, the active ingredient, a vesicant used as a defence by L. vesicatoria and other blister beetles.
   • 2010, Carol Turkington, Deborah R. Mitchell, cantharidin, entry in Encyclopaedia of Poisons and Antidotes, 3rd Edition, page 49,

     Ingestion of Spanish fly causes burning in the throat and sloughing of the upper gastrointestinal tract.

   • 2012, Richard Webster, The Encyclopedia of Superstitions‎, page 11:

     The best-known aphrodisiac is Spanish fly, which is made from the wings of the blister beetle. Spanish fly creates a condition known as priapism in men. This is long-standing erection, which sounds good in theory. Unfortunately, Spanish fly removes all sensitivity from the organ, rendering it ineffective. In women the results are more severe. These include depression, vomiting, inflammation of the kidneys, and even death.

2. (countable) The beetle Lytta vesicatoria.
   • 1850, Thomas Duché Mitchell, Materia Medica and Therapeutics‎, page 248:

     The Spanish fly abounds in the south of France, Spain, and Italy, and is found on the ash, lilac, privet, elder, honeysuckle, plum, willow, and elm trees. […] The American fly is rather smaller than the Spanish fly, and of a much darker color.

   • 2003, T. F. Allen, Hand Book of Materia Medica and Homoeopathic Therapeutics‎, page 266:

     Spanish flies applied to the skin produce blisters (vesication, with inflammation and even sloughing).

The synonyms cantharis and cantharides and associated taxonomic classification are regarded by some as obsolete and incorrect, but are still sometimes used; Cantharis is a genus of not closely related but superficially similar beetles of the family Cantharidae. (See also Cantharis on Wikipedia.Wikipedia )

• (supposed aphrodisiac): cantharis, cantharides
• (Lytta vesicatoria): cantharis

• blister beetle
• meloid