mothguide.com Cabera variolaria
(Pink-striped Willow Spanworm)
This species is very similar to erythemaria, but there are some distinguishing characters:
1) variolaria rarely has median line on FW, erythemaria usually has it.
2) variolaria is often almost entirely white
3) AM and PM lines are sharper and straighter than on erythemaria.
Protitame virginalis is also quite similar.
Lomographa vestaliata, though clearly different in appearance, often comes out at the same time of year and could be mistaken at first glance.