Leg Cutter Wasp

Has anyone seen this little wasp I call it the Leg Cutter. She's about 20mm long, black body with orange antennae. It stings its prey then bites its legs off before taking the body away. The only spiders I've seen it prey on are black house spiders and quite often the spider is a lot bigger than the wasp. It holds the rear end of the spider, straddles it then drags it along. It will climb to gain height then launch itself and fly a few feet before crashing back to earth, then repeating the process. I've never seen it actually biting the legs off just the result.
Cheers,
Geoff.

I believe this are known as spider wasps, some do remove the legs and some don't, and are found all around the world.

S