The species is very similar to
Perizoma affinitata in colour and pattern but often has a double indention in the inner margin of the band. It is also smaller. "Very similar to
affinitata but smaller, with clearer and more regular white marks at the hindmargin of the forewing, tendency towards obsolescence of the pale band on the dark hindwing; distal area of forewing with black dushes on the veins. Generally less variable than
affinitata. —
peterseni notn. nov. has the white antemedian band well expressed; generally also the postmedian white band is somewhat widened and sometimes even a complete white subbasal is present. It is the prevailing form in
Estonia and perhaps in
Scandinavia and is commoner in
Scotland than in
England, but occurs as an aberration in many localities." The larva is short and powerful, with some short bristles. It is light green with two red longitudinal stripes along the back. ==Biology==