I saw @mamestraconfigurata’s Noctuid moth identifying features tutorial, and I was inspired to make my own tutorial on features of Peppered Moths of America, mainly Biston betularia cognataria. Until more observations are found of Biston betularia contrasta, besides the one observation by @jimjohnson, I will not include the other subspecies here.
The first picture shows a specimen of B. b. cognataria.
Original observation https://www.inaturalist.org/observations/60393954 by @chloejreid, September 19, 2020.
The second picture shows the underlying vein structure of an American Peppered Moth, which may or may be visible for all specimens.
Original observation https://www.inaturalist.org/observations/51329294 by @chloejreid, June 28, 2020.
And here is the explanation that I typically use to describe B. b. congnataria:
This could be a male Biston betularia cognataria morpha typica. Males have narrower thoraxes than females, but since bushy antenna are not visible, it is impossible to absolutely verify that it is male. In contrast to other similar looking moth species, the Peppered Moth does not have as many bold latitudinal lines, nor does it have prominent edge scalloped spots. The range of B. b. cognataria is only North America (Müller, Bernd, et. all. “Ennominae II: (Boarmiini, Gnophini, additions to previous volumes).” Google Books , BRILL, pp. 306, 2019, https://books.google.com/books?id=lS2hDwAAQBAJ&pg=PA304&lpg=PA304&dq=Amphidasis+cognataria&source=bl&ots=vcji5QPrkY&sig=ACfU3U06TEG2nJSo7oOAAWZ2xl3juXUEig&hl=en&sa=X&ved=2ahUKEwjGwYvT_OHrAhVGCM0KHfCVAtUQ6AEwEnoECAgQAQ#v=onepage&q=Amphidasis%20cognataria&f=false. Accessed 7 September 2020).
Upon comparison to the nominate European subspecies Biston betularia betularia , the American subspecies appears darker and has more pronounced lateral lines. This gives them a unique “Cookies-and-Cream swirl” effect. Moreover, this specimen should be white morph due to the spotting wing pattern being clearly discernible on a cream-colored wing background. Although, the weirdly translucent and barren forewings partially obscure the back wings, which do not have the characteristically clear costal dark triangular markings or the transverse medial or post-medial lines.
These websites helped me to make this short wiki: