I have been struggling to ID this photo and am confused. My best guess would be a female Horace's rather than Juvenal's based on the following information from Cech & Tudor (2005), Butterflies of the East Coast: flight time (Horace's is earlier), location (Horace's more likely on immediate coast), Horace's female wing more patterned, Horace's wing with "extremely prominent glassy hyaline spots", Horace's distribution goes further south. I haven't seen either one live so I might be completely wrong. Would someone explain what I'm missing. Thanks.

I happened upon this thread because I had a Duskywing in Florida yesterday.

Males like this have a costal fold at the leading edge of the forewing.
One needs to compare female to female and male to male of the different species.

The gray overscaling (like this) is usually more associated with Juvenal's.

Horace's are multi-brooded and fly year-round in Florida. Juvenal's have one flight in the early spring. In other areas generally, the flight of Horace's begins as Juvenal's is ending. There is some overlap, usually mostly in April. Please take these comments as general.

Juvenal's often has a couple pale apical spots on the ventral hindwing that can be helpful with the ID.

The white "frosting"- actually white hairs when viewed through a hand lens- on the forewings makes this a male Juvenal's Duskywing. Horace's lacks these white hairs and is generally later. Duskywings are one of the toughest groups of butterflies to ID, especially considering the varying information found in different reference works.