Perconia strigillaria, the grass wave, is a moth of the Geometridae family. The species can be found in Europe East to the Urals, Asia Minor and the Tarbagatai Mountains (China). The wingspan is 36–41 mm. The forewing ground colour is white with fuscous irroration. The crosslines are wide The antennae are comb-like."White, with fuscous irroration; all the lines present, usually also a subterminal dark line. Median line (or shade) variable in position and thickness. - ab. herpeticaria Rbr. Antemedian and median lines of wing thick and closely approximated, sometimes confluent into a band. - grisearia Stgr. is a greyer form the white ground-colour nearly suppressed. Frequent in N. Europe, but not very sharply separable from the name-type. Most British examples are intermediate. - cretaria Ev