Butterflies and Moths of North America

collecting and sharing data about Lepidoptera

Horace's Duskywing
Erynnis horatius (Scudder & Burgess, 1870)


Family: Hesperiidae
Subfamily: Pyrginae
Identification: Fringes are brown. Upperside of male forewing is dark brown with little contrast and no white overscaling. Upperside of female forewing is light brown with a contrasting pattern and large transparent spots. Underside of hindwing is usually without 2 spots below the apex. Male has a costal fold containing yellow scent scales; female has a patch of scent scales on the 7th abdominal segment.
Wing Span: 1 7/16 - 1 15/16 inches (3.6 - 4.9 cm).
Life History: To seek females, males perch at the ends of twigs on hilltops or slopes about 1 foot above the ground. Mating has been observed around midday; females deposit eggs singly on new growth of the host. Caterpillars feed on young leaves and rest in leaf nests. Caterpillars of the last brood hibernate.
Flight: Two broods in the north from April-September, three broods in the Deep South and Texas from January-November.
Caterpillar Hosts: Both red and white oaks including willow oak (Quercus phellos), northern red oak (Q. velutina), scrub oak (Q. ilicifolia), water oak (Q. nigra), post oak (Q. stellata), and live oak (Q. virginiana).
Adult Food: Horace\'s Duskywing visits flower up to about 4.5 feet tall including dogbane, buttonbush, sneezeweed, goldenrod, peppermint, boneset, and winter cress.
Habitat: Open woodlands and edges, clearings, fencerows, wooded swamps, power-line right-of-ways, open fields, roadsides.
Range: Massachusetts west to eastern South Dakota; south through most of the eastern United States to Florida, the Gulf Coast, and South Texas; south in the west through southeastern Utah, Colorado, northeastern Arizona, and New Mexico.
Conservation: Not usually required.
NCGR: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
Management Needs: None reported.
Comments: NULL