This page will eventually have an explanation of how best to identify moths along with the principles of species identification generally. For now, it has two collages illustrating intraspecific variability in forewing markings.

Figure 1. Hypsopygia olinalis (Pyralidae: Pyralinae) photographed on a single night at a single site, 26 June 2022, on Block Island. View full size image.
Figure 2. Macrochilo orciferalis (Erebidae: Herminiinae) photographed on Block Island from 2020 to 2022, all but two at the Hunt property and all but two or three male. View full size image.