Prorella leucata Wikipedia
Prorella leucata is a moth in the family Geometridae. It is found from California through Colorado, Maine, Montana, Oregon and Utah to British Columbia.
The wingspan is about 20 mm. The wings are pale creamy, blotched with blackish along the costa. Of these patches, a rectangular, pre-apical one and a median one just interior to the discal spot are the most prominent. Adults are on wing from June to September.