New Jersey Butterflies

Horace's Duskywing

Erynnis horatius

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 glassy spots in FW are much more prominent. 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. Often 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 partial third from September into October. The second brood is by far the largest. Extreme dates: North Jersey 4/29—10/15; South Jersey 3/23—10/24.

Caterpillar Food Plants: Oaks (Quercus), especially young trees with tender leaves.

Overwintering Stage: Caterpillar.

Good Locations: Any dry field near oaks is worth checking.

Comments: From April through 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 late June 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.