Local feeder (Diptera: Cecidomyiidae) in petioles of Anemone

In autumn 2021, I discovered several larvae of this local feeder in the interiors of basal leaf petioles of hepatica and thimbleweed. At this time the larvae had finished their feeding and spun pale cocoons for overwintering. No clear external evidence of the larvae's presence in the petioles was visible, but internally the thimbleweed petioles contained some blackish discoloration around the larvae, apparently due to the presence of a symbiotic fungus. R.J. Gagné (pers. comm.) examined examples from both host plants, and determined that they belonged to the genus Neolasioptera. It is not known whether larvae from the two different hosts belong to the same species of Neolasioptera.

Furthermore, in late August 2025 I found a browned area on a basal leaf petiole of thimbleweed growing along my driveway. A single small exit hole was visible in the center of the browned area. Dissecting the petiole at this point revealed a spent cocoon inside, with its anterior end opening into the exit hole. I was then able to extract the larva's spatula from inside the cocoon and photograph it, confirming the identification to family level.