General ID features: A visual guide to the most common features used to identify Noctuid moths.
Noctuid moths mostly have the same general features used for identification. The moths can vary amazingly in their general colouration and modifications of these features. I thought I would make a visual guide to the general features of these moths, as well as address features of individual common moths that I often find misidentified. A lot of these markings are used for other moth groups (i.e. Geometridae).
Eudryas grata/unio: These were new moths to me in 2021, and all identifying information only talked about the differences in scalloping at the terminal end of the wing. Sometimes the scalloping is difficult to discern and there appeared to be other differences besides that one feature. I had to go back to Forbes (1954) for a description of the two. My journal entry contains a link to a discussion which has the Forbes descriptions quoted, so I will not add them here.
[Eudryas spp. · iNaturalist.ca]
Photos courtesy of CBIF
Egira dolosa: Often hard to identify. This is an early flying moth. The white stripe that runs from orbicular to orbicular (when the wings are closed) may have an orange hue, or else be faint or even absent. The overall black/white colouration, and the white collar do not change.
Photo courtesy of CBIF
*Hyppa spp.
**Photo courtesy of CBIF **
Mythimna unipuncta: There only two Mythimna species in North America. This is one of them. There are moths in the same genus outside NA that look like this species, but are no. This is only for North America. The other species is M. oxgala (see below).
Mythimna oxygala: This is the second Mythimna sp. Very different from it’s sister species, but the three black dots are easy to see. I also find this one to be frequently misidentified. Either the dots are not there, or it is classified as a Leucania spp.
**Photo courtesy of CBIF **
Agrotis ipsilon:
Feltia spp.
A confusing Genus. These are the four most common species, often mis-identified because they look so much alike:
All Photos courtesy of CBIF
Feltia jaculifera: This is the easiest of the genus to identify. Its characteristic terminal ‘W’ is not found in any other Feltia spp.
Feltia herilis: The second distinctive species. A worn specimen can often be tougher to identify, but the orbicular spot is usually conserved.
Feltia subgothica/tricosa The only reliable way to tell these two species apart is to look at their antennal bristles. The difference is here - (https://www.ndsu.edu/ndmoths/ndmoths/names/10674.htm). I have found it is sometimes possible to make out the bristles clearly enough for an ID, but often they are blurred, the antennae are not visible, or the moth is female. iNaturalist now has a Complex - Subgothic and Tricose Darts which is best used when a firm ID cannot be made.
Bugguide has a somewhat confusing description (https://bugguide.net/node/view/10466) that I no longer use. Important features to notice is the mounded orbicular spot which is not the same colour as all the costal streak. As well, there is no ‘W’ as found in *F. jaculifera.
F. subgothica has shorter antennal setae.
F. tricosa has longer setae. 
This is only a rough guide. Due to variation and wear, it may not be possible to identify these moths visually, in which case (after Feltia jaculifera & F. herilis have been ruled out), genus Feltia Complex would be the prudent option.
Peridroma saucia: I have noticed that this species is often confused with Noctua pronuba. They do have some similarities (shape and large orbicular spot) but the 7 costal marks and overall mottling are usually enough to distinguish P. saucia.
Photo courtesy of CBIF
Graphiphora augur
G. augur is a drab moth, often with few markings. Usually the dark spot on the posterior reniform remains visible even with worn moths.
Photo courtesy of CBIF