I was out looking for the elusive snow fly yesterday but found this, instead: an eastern stonefly (Allocapnia recta), a member of the Capniidae (small winter stoneflies). At least that’s what I think it is. Larvae are active during the winter, and adults can fly and mate even when temperature is in the teens. Pretty incredible to see them flitting around on a cold day when other insects cannot even move. At Hildacy Farm in Media, PA. Probably emerged from the nearby Crum Creek.