Has this been posted already?
It's a full mexican movie called "La Loba" (She-Wolf) from the early 1950s. Cheap effects, with werewolves obviously inspired by The Wolfman but entertaining in a Plan 9 from outer space kind of way.
The main "transformation" starts around 1:00:00, but you can see the She-Wolf at several points in the movie.
https://www.youtube.com/watch?v=8fCgGmen7Rs