oddly enough, "las vampiras" doesn't quite have a one word English translation, does it? "vampiresses" is a very clunky word. too many sibilants!
there were many Santo movies and other Mexican movies shown in the early mornings in my area growing up, but I had no idea what they were, since they were listed in Spanish in the TV Guide. I am sure I would have watched all three of the Santo movies in English had they been aired, with those titles, since they referenced monsters directly, and he was dubbed Samson (or the Saint in the case of "Invasion of the Zombies"). alas, none of them appeared.
the early b/w Santos are the best of his peliculas, though.