Sounds like Japanese beetles. They are all over the trees in Northern New Jersey. They have shiny red shells, they fly, and they stack atop one another.When we came through Louisiana for our honeymoon in August 2000, we found these bugs which were some sort of flying beetle. We called then sex bugs since they seemed to spend their whole life intertwined in the air with a mate. They stuck to the bumper of our car and no matter how many times we washed the dam thing, some reminents of them remained.