Rheumaptera undulata, the scallop shell, is a moth of the family Geometridae.

The outer margin is pale brown with a scalloped fringe.

The dorsum is light to dark grey, with narrow white longitudinal stripes.

[4] There is one generation per year with adults on wing from the end of May to August in Europe.

The larvae feed on birch (including Betula verrucosa and B. pubescens), Vaccinium (including V. myrtillus and V. uliginosum) and willow species (including Salix myrtilloides, S. caprea, S. aurita, S. cinerea, S. myrsinifolia and S. phylicifolia), as well as aspen (Populus tremula), Populus balsamifera, Berberis vulgaris, Ribes alpinum, Spiraea salicifolia, rowan (Sorbus aucuparia), Elaeagnus commutata and Myrica gale.