Flower flies (Diptera: Syrphidae) are a ubiquitous family of true flies known for their hovering mating displays and pollinating behaviour. The flower fly genus Pterallastes Loew is represented by Pterallastes thoracicus Loew in North America, and its previously published range encompasses only the United States of America. Here, we report two new records for Canada and a previously overlooked historical record for the country. These data were used to generate an updated range map for the species, with additional iNaturalist records further expanding its known distribution in the United States of America. Finally, flower associations and natural history data for the species gathered from iNaturalist photos are discussed briefly.