Fly

You may be right with wasp, I was thinking Drone-fly but don't have much info on Spanish ones
The Butterfly has its own spotting, see notes.
Cabbage White is a generic name covering more than one species over here but is usually used for the Large White (Pieris brassicae) as it is that one which can decimate the cabbage crops. Only the second brood of Pieris rapae feeds on cabbage and does significantly less damage. The accepted common name for Pieris rapae is Small White.

That looks more like a wasp to me-
The butterfly is a Cabbage White Butterfly (Pieris rapae)
http://en.wikipedia.org/wiki/Pieris_rapa...