Stem borer (Diptera: Agromyzidae) in Carex

I found puparia in tunnels in the interiors of senesced culms of the host in winter 2022-2023. They were reddish-brown, widest at the front and tapering significantly to the posterior. Immediately above the anterior end of each puparium in the culm, an elongate-oval exit window was present in the wall of the culm, which had been prepared by the larva prior to pupation. Adults emerged from overwintered puparia in spring.