I recently posted this question:
Can you name the plant, and the bug that makes these markings? Should be easy!
Prem and Scott both suggested, correctly, that the bug that does this is a leaf miner. I apologize that I can't call out the exact type. Scott suggested that the plant is Aster cordifolius, (Heart-Leaved Aster), and that is correct. Good work Prem and Scott!