These pretty red blister beetles lay their eggs in the nest of Colletes bees. No surprise then that in addition to this beetle, I saw several others along with hundreds of the small Colletes bees. The bees are solitary bees, but nest in large aggregations in early spring in sandy soil. They are an important pollinator, and no, they don't sting (or so rarely as to be exceptional... I was in the midst of scores of them today and had them crawling on my hands with no issues!).
For a photo of the Colletes bee, see: http://www.pbase.com/laroseforest/image/134175789