Pero ancetaria, Hübner's pero, is a moth of the Geometridae family. It is found in the eastern part of the United States, Ontario and Quebec. The wingspan is 31-37 mm. Adults are on wing from March to September in the south (from May to June and again from August to September). There are two generations per year. The larva feed on Alnus, Shepherdia canadensis, Prunus serotina and Salix.