An 'aria'
Is generally known as an 'aria'
Most bands using those elements compose them on their own, rather than sampling. On the first Cadaveria album, the intro to the opening track "Spell" seems to be sampled from an Opera record,...
An Aria
One can only assume you're referencing the Habanera. Specifying characteristics would help to find a more precise answer.
It was Carmen. Check the answer: http://www.imsdb.com/scripts/Magnolia.html