Perizoma affinitata, the rivulet, is a species of moth of the family Geometridae.

It belongs chiefly to northern or mountain districts, but sometimes occurs as an aberration with the type England, N. Norway, the Alps, Carpathians.

and Verity is larger, the forewing grey, not brown, but darker than in hydrata and with broader white band; hindwing greyish with double whitish band; underside like that of rivinata.

[2] The larva is rather powerful, pale pink with a dark head capsule and the dorsal side of the first body joint.

The species is found in forest edges, hedges and on flower meadows.