Spanish fly

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A brilliant green blister beetle (Lytta vesicatoria) of central and southern Europe.
• noun A toxic preparation of the crushed, dried bodies of this beetle, formerly used as a counter-irritant for skin blisters and as an aphrodisiac.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun uncountable cantharides, a supposed aphrodisiac prepared from the dried and ground bodies of a variety of blister beetle, Lytta vesicatoria
• noun the beetle, Lytta vesicatoria

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun green beetle of southern Europe