VIDEOS: Larvae feeding #1 ~ Larvae feeding #2

Gregarious dipterans mining a leaf of Maianthemum dilatatum

Offhand I can't find any previous records of this sort of thing on Maianthemum, but Eiseman (2018) reports "scathophagid larvae forming blotch mines in Trillium ovatum [also in order Liliales --John v.] in Washington in early October. On some leaves, the elongate, white eggs were attached to the lower surface in clusters of 2–3, while one leaf had one group of 8 eggs and another group of 18." (p. 518)

Source: Eiseman, C. 2018. Leafminers of North America