A second new species of Boletina Staeger fungus gnat was discovered in western Michigan following the discovery of Boletina michigana Taber in the same habitat at the same time of year. Males and females were collected in early spring in a Malaise trap in a paper birch (Betula papyrifera Marshall)-red maple (Acer rubrum L.)-black cherry (Prunus serotina Ehrhart) woods adjacent to black ash (Fraxinus nigra Marshall) swamp and cattail (Typha latifolia L.) marsh. Boletina setacea Taber will key out to Boletina sciarina Staeger by using one of two old keys, but male terminalia and wing venation indicated a specific difference.