Actually, it looks more like a female Juvenal's to me. Notice on the forewing, beside the large upper pale patch, that there is a broken row of small white markings going downward from the costal wing margin. On horatius, there are only 6 of these smaller pale white markings in the row, because the bottom 2 are completely darkened. However, juvenalis has 8 or 9 with the bottom 2 always being at least partially pale white as seen in your picture. Now compare to this picture of a horatius
where only 6 pale white spots are in the row - 4 from the costal wing margin and 2 slightly lower. Notice the bottom 2 would-be pale spots are completely darkened (or sometimes absent in the male). These can be tricky to ID, but this is one way that I've always understood as a means to distinguish these two species. Hope that helps.

to sp. page

but this is a very close match for Horace's duskywing, Erynnis horatius, female, in Butterflies through Binoculars(1).