Ophiomyia mines on E. purpureum observed during the current study tended to spiral around the stem, creating a distinctive pattern. It appeared that frass was typically deposited along the edges of the mine. On E. purpureum, the miner pupates just under the epidermis of the stem at the very base of the plant, with the anterior spiracles projecting through the epidermis. Adults were reared in 2022 from overwintered puparia on stems of E. purpureum. Apparent Ophiomyia stem mines were also observed on E. maculatum, and a stem mine with a puparium was noted on a cultivated Eutrochium in a garden setting. It is not known whether the mines on E. maculatum, E. purpureum, and the cultivated Eutrochium are all created by the same species.