Globular or bullet-shaped swelling on upperside of leaflets along veins, opening on lower surface of the leaflet ... Dasineura pellex (Osten Sacken)
Galls may be green, purple, or black. The white larvae drop to the soil in about the second week of June in Maryland and overwinter there. Adults have not been reared. ...Host: Fraxinus sp. Distr.: throughout eastern North America.
”- Raymond J. Gagne: (1989) The plant-feeding gall midges of North America©