Eupsilias are robust Noctuids that overwinter as adults and are sometimes active during warm spells during the winter. There are seven Eupsilia species in the east, five of which sport a white or orange reniform spot flanked by two tiny dots, one on each side. This marking resembles Jupiter flanked by its moons when seen through a pair of binoculars. The mark is very distinctive, and readily narrows identification down to five species.
Once the identification is narrowed down to this species group, however, things become much more difficult. Many moth-ers refer to moths with this mark as Straight-toothed Sallows (E. vinulenta) and leave it at that, but most of these species cannot be distinguished from each other by photographs and are best referred to as Eupsilia sp. or Straight-toothed Sallow types. The exception is the Three-spotted Sallow (E. tristigmata), which has a noticeable orange orbicular spot and a dark spot in the inner part of the reniform spot.
Straight-toothed Sallow can be distinguished from its close relatives by details of forewing scale structure. The forewing scales end with straight (not curled) teeth. This may be visible under high magnification; see, for example, this photo from BugGuide and compare it with a similar photo of Franclemont’s Sallow (E. cirripalea), which shows curly scales like strands of hair.
According to Wagner et al. in Owlet Caterpillars of Eastern North America, Straight-toothed and Three-spotted Sallow are found throughout New Jersey. An undescribed yet common species is mainly found in northern Jersey, while Franclemont’s Sallow replaces the undescribed species in the southern part of the state. Sidus or Barrens Sallow (E. sidus) is most likely to be found in barrens habitats and is at best local elsewhere.
I have found Eupsilia sp. moths from November through March, with most records coming from either of those months (March has a slight edge). Wagner et al. state that Sidus Sallow flies later in the season (sometimes into May) than its relatives.