Un Chien Andalou - What's the name of the tango in the beginning?

I heard it was Argentinian, but who knows. Other people on the internet don't seem to, but maybe you do?

Check it out (streaming and/or direct download options): http://www.ubu.com/film/bunuel.html

It's the first song in the film, and just to be clear no i'm not wondering what the title of the wagner piece that's used.

Even if you don't know the song, check out the film if you haven't seen it! it's short, surreal, and is notorious for being whacked the fuck out.