With bugs it's much, much harder. There are just so many of them. So when I looked in Dominique M. Collet's Insects of south-central Alaska I found one that looked pretty much like this moth I photographed last night in our bathroom. But how much variation is there?
|Late night visitor|
The moths of this family are mostly cryptic* like Autographa,, which is almost invisible when resting on birch bark. A few noctuids like Androloma and Alyopia are brightly contrasted.The one called Semilooper Autographa sp. looks most like the one that visited last night.
This moth is mottled grey or brown with a white or yellow comma-shaped spot in the middle of its forewing. The moth is well camouflaged when resting on birch bark with lichens. Newly emerged moths have tufts of hair on the back that break up its silhouette and help it resemble the rough bark scars on trunksThe shape matches that of the one in Collet's book. The size is right (about 3/4".) It's got the little spots on the wings, but not quite commas. And its rump looks hairy, is that the 'back'? The diagram that shows body parts on page 19 doesn't identify 'back.'
The caterpillars are cutworms, so that would work. Ah, the joys of trying to 'know'.
While trying to confirm this online, I did find a great page full of similar, but much better photographed and much more interesting moths at the site of the Mississippi State University Entomological Museum.
*Definitions.net includes this 4th meaning of cryptic:
4. Zool. fitted for concealing; serving to camouflage.