This tiny fly is one of the many, many species of fruit flies that occurs in eastern Ontario. These are not related to the tiny flies that cluster around bowls of fruit at home. These belong to the family Tephritidae, and many are specific to various types of plants, such as sunflowers, apples, walnuts, etc. The fly that makes the galls on goldenrods belongs to this same family. This may be in the gentus Urophora. It was found on a red-osier dogwood.