Identification: Very small—1.45" but the largest Erynnis in NJ. Above: FW mottled dark brown with little gray overscaling. Several glassy spots in FW, including a wrist "bracelet," and 2 additional spots aligned with it; and a small, white, cell-end spot. HW dark brown with inconspicuous, blurry, submarginal spots. Female is much more conspicuously mottled above on both wings, and has much-more-prominent glassy spots in FW. Below: FW and HW in both sexes dark brown, with a few glassy marks usually visible in FW; lacks pale spots along leading edge of HW. (However, like all duskywings, Horace's is most often seen spread-winged, so the presence or absence of these spots may be difficult to determine.) Other: Palps ("face") usually white, and white extends as a ring over the eye. Similar species: Juvenal's Duskywing is virtually identical above except that the female is less highly patterned than Horace's and has smaller glassy spots in FW. Below, Juvenal's has 2 pale spots along leading edge of HW that Horace's lacks. Juvenal's also has a dusky "face" and lacks a white ring over the eye. Wild Indigo Duskywing is slightly smaller, blacker above (especially the male), with smaller glassy spots in FW, and lacks cell-end spot above.
NJ Status and Distribution: Resident. A primarily southern species that is near the northern limit of its range in NJ. Uncommon but widespread in northern counties; more common in southern counties.
Habitat: Dry fields near woods with oaks. Occasionally visits gardens, especially those near oak woodlands.
Flight Period: Two or three broods, mainly from May into June and July into August, with possibly a third from September into October. Extreme dates: South Jersey 3/23—10/24.
Larval Food Plants: Oaks (Quercus), especially young trees with tender leaves.
Overwintering Stage: Larva.
Best Locations: None, but any dry field near oaks is worth checking.
Comments: In May and June care must be taken to distinguish Horace's from Juvenal's as both are flying, and the less-common Horace's may be overlooked. However, a large duskywing seen from July on is almost certainly Horace’s, as Juvenal’s are not known to have a second brood in NJ. In North Jersey in summer the active field observer is lucky to see 1 or 2 Horace's per day, whereas in south Jersey 5 or more on most days would not be unusual.
Male, Great Swamp NWR, Morris Co., NJ, 7/4/09.
Female, Lakehurst, Ocean Co., NJ, 7/8/06.
Great Swamp NWR, Morris Co., NJ, 7/1/06.