Stem borer (Coleoptera: Tenebrionidae) in Andropogon

I found a larva boring in the very base of an overwintered dead culm of the host in a "postage stamp" remnant prairie in early May. According to my records, the larva pupated on 14 May and the adult emerged on 28 May, but no further details were recorded. The overall impression from the situation was that the larva had been present in the culm over the winter, having begun tunneling in it when the plant was still alive in the previous growing season, but this interpretation was not confirmed, so the record of this species as a herbivore (rather than a detritivore) is tentative. Mathison (2017) identified the adult from photos.