In the 20th century, five species of birch-leafmining sawflies were inadvertently introduced from Europe to North America: Heterarthrus nemoratus (Fallén), Fenusa pumila Leach, Profenusa thomsoni (Konow), Fenusella nana (Klug), and Scolioneura vicina Konow. All have been recorded at outbreak levels in North America, and three (F. pumila, P. thomsoni, and H. nemoratus) have been the targets of successful biological control programs. The most recently detected species, F. nana and S. vicina, are good candidates for future biological control in Canada. We review the biology of all five of these birch-leafmining sawflies in North America and present keys to adults, larvae, and mines to aid correct identification.