This turned up on my kitchen windowsill this morning. Unfortunately it was dead, and became progressively more dried up as the day went on. It has a "wasp waist" so presumably is a wasp, but what kind?
Before it got too dessicated I could just make out what looked like some grey bands, either on the thorax or abdomen. It is about half a cm long including the antennae, perhaps a bit more if the body ws straightened out. The body is mostly black and the legs and wings yellowish brown.