Your beetles (not bugs) are American Carrion Beetles (Necrophelia americana). Come back in a week and there won't be a morsel of flesh left unless something bigger joins in.
The turtle appears to be a bashed Eastern Painted Turtle.
It could possibly be saved by irrigating the wound to get dirt, bugs and debris out using hydrogen peroxide. And to close the shell, super glue or epoxy a piece of plastic over the area where the shell was damaged.