Matt Wright found this handsome specimen — and dozens like it — feeding in one of his blooming hedges.  A trip around the newsgroups identified this as a tarantula hawk (Pepsis sp.).  It’s a large wasp — females apparently have a nasty sting.  Its favorite food — besides blooming hedges — is tarantulas.  After paralyzing the big spider, they drag it to its lair, where the female wasp lays a single egg.  The pupa enters the spider abdomen, then feeds on the inside of the spider, avoiding vital organs to prolong its life, before pupating and bursting free from the abdoment as an adult wasp.  Lovely!  But if you don’t annoy them, they’re quite lovely to watch.