"The worm is only found in mescal (mezcal). The adding of a worm to tequila is prohibited by the Mexican Standards Authority. The worm is one of a number of species that feed on the agave plants that mescal is made from and was first added in the 1950's as part of a marketing gimmick. A mescal containing a worm is usually labelled 'con gusanos' meaning 'with worm'."
yay for google ;o)
at 2:06 PM on Jul. 5, 2010