Hard to say when it happened. I was reviewing this record from 1984 and noticed what looked like caterpillar bites. I thought, how incredible. They have preserved record or monarch activity in 1984 on Hall’s milkweed. Then I looked at the rest of the record and see how the flowers are mostly disappeared and the leaves are eaten by something other then a caterpillar and most likely after the plant was pressed. Maybe the bug was pressed with the plant and ate for a few weeks and died?