Alloperla aracoma Harper and Kirchner

was previously reported from only one Pennsylvania stream, Powdermill Run, Westmoreland County, in the Conemaugh River portion of the Ohio River basin (Grubbs 1996). Maryland and West Virginia are the only other states with records of A. aracoma, where it is restricted to the Allegheny Plateau and the Ridge and Valley Physiographic Provinces (Surdick 2004).

New record: SOMERSET: (S) Breastwork Run, first SR 1017 bridge south of US Rte. 30, 29 June 1994, 1♂. Breastwork Run is a small forested cold water creek in the upper Juniata River portion of the Susquehanna River basin, along the eastern flank of the Allegheny Front near the divide with the Ohio River basin.