This bug and millions like him/her were at our campsite at St. Croix State Park this weekend. They looked like dark specks of dirt and there were approximately 500 of them per square foot. When disturbed, they hopped 3-6 inches and redistributed themselves evenly all over the ground. They didn't seem to prefer a particular time of day, and didn't bite (that I know of). I've looked all over the internet and can't figure out what they might be. I would really appreciate any help.