Slug:
This is a cicada killer wasp (Genus Sphecius). You can read about them, but in short, they burrow in the ground and kill one cicada, which they bring into the burrow for all the eggs to feast on after they hatch. I happened to walk into a colony of them, where burrows were spaced out every 2 feet. They are large and fly very slow and apparently have trouble seeing because they have no problem flying right into you.
This is another view of the very common monarch butterflies (Danaus plexippus).
I'm not sure which dragonfly category this individual belongs to...