yeah, ive seen bluish colored wasps grabbing spiders and burying them in a hole in the ground. i guess they paralyze the spider and let it sit there for a while. i would watch and then sometimes a lizard would grab the spider before the wasp could finish its job. i think the wasp plants an egg on the paralyzed spider and then when the egg hatches it makes a meal of the spider.
a few years ago i saw these huge huge bluish silver wasps like 3 inches long and they were buzzing around an oak tree about 10 feet up. i think they were grabbing caterpillars.