Length: 5-6 mm
A study of insect visitors to tall grass prairies in Manitoba showed Toxomerus marginatus as one of the two most common species to visit flowers, and T. marginatus ranked number one in the number of flower species it visited (twenty-eight).
Tooker, Hauser, and Hanks (2006) labeled Toxomerus marginatus as an aphidophagous species. They also cited several authors who have stated that the species "can be an important pollinator."
Toxomerus marginatus is a very small fly that ranges from British Columbia to Quebec, south to California and Florida, and on into Central America.
American Insects site