At just 5 mm, this is the tiniest stonefly I’ve ever seen! Furthermore, he was out on a day in February when we just barely got above freezing for a little while. I think this is a member of the “small winter stoneflies” or the family Capniidae. I suspect it is in the genus Allocapnia. Insects that come out in the middle of winter fascinate me…see my post on insects that specialize on snow!