Swollen leaf vein fold
Folds are elongate, 5-10 mm long. Only a slit shows on the upper side of the leaf; on the bottom side the galls are convex and yellowish. Full-grown larvae escape through the slit on the upper side.
Host: H. discolor.
Distr: Oregon
- Raymond J. Gagne: (1989) The plant-feeding gall midges of North America©