As far as I can ascertain, this is the typical life history of this species:

1. Young larva induces narrow, tapered swelling or gall on upper stem of its hostplant, prairie sage (Artemisia ludoviciana), as it feeds inside the stem
2. While still relatively young, larva exits gall, crawls downward, and bores into the stem at some point below the gall



3. Larva continues life as a stem borer, feeding and growing in the lower stem for the remainder of the growing season
4. Larva overwinters in lower stem

(see also the current series)

5. In spring, larva pupates in stem and adult emerges



This image shows a dead stem of prairie sage with a vacant upper-stem gall, collected in May after stem and gall overwintered in the field. Other images in this series show closeups of the vacant stem gall; a mature larva dwelling in the lower portion of the same stem (where it had been since the previous summer); and typical woody frass filling the stem near the larva's dwelling-place.