Jim noticed this white moth with a distinctive black dagger marking, when both wings are closed, on a woodland trail during one of our frequent hikes. It is a Haploa clymene. Take notice of the black edges on all three sides that make it appear smaller.
Bug Guide came to the rescue again by identifying it for me. See some other photos of it at ButterfliesAndMoths.org that show the wings open, revealing previously-hidden yellow markings on half the body.
Bug Guide says that this does not have a “common name” and it makes me wonder how “common names” come to be official.
I have these fantasies of capturing these specimens in a jar and starting a collection, but I don’t like the idea of taking anything more than my camera/phone on my hikes. I need to think about this more. If any of you have ideas for making it simpler or have collections of your own, please share tips on how to make it an easier process than I am thinking it might be.