The wingspan is 60–65 mm.
The forewings are grayish brown above, with a clearly marked irregular black line running from the leading to the trailing edge both inwards and outwards of each wing's center.
The upperside of the hindwings is mainly yellowish orange, with a few dark hairs at the base and a blackish pattern.
The latter usually forms two roughly concentric bands, an inner one curving through the mid-wing from the leading to the trailing edge, and an outer one that almost reaches the termen.
The apex is outside the outer band and forms a large bright orange-yellow spot; likewise, the outer band does not reach the tornus, which bears a separate black spot.
The termen has faint dark bands along the wing veins.
The underside of the wings is yellow with black bands.
Some forms with aberrant pattern are known.
As in many relatives, the foreleg tibia of this species possess no spines, while the tarsi carry three rows of spines.

Adults are on the wing from May to June depending on the location.
There is probably one generation per year.
The caterpillars feed on such plants as bur oak (Quercus macrocarpa), Gambel oak (Q. gambeli), and willows (Salix).
The wingspan is 60–65 mm. The forewings are grayish brown above, with a clearly marked irregular black line running from the leading to the trailing edge both inwards and outwards of each wing's center. The upperside of the hindwings is mainly yellowish orange, with a few dark hairs at the base and a blackish pattern. The latter usually forms two roughly concentric bands, an inner one curving through the mid-wing from the leading to the trailing edge, and an outer one that almost reaches the termen. The apex is outside the outer band and forms a large bright orange-yellow spot; likewise, the outer band does not reach the tornus, which bears a separate black spot. The termen has faint dark bands along the wing veins. The underside of the wings is yellow with black bands. Some forms with aberrant pattern are known. As in many relatives, the foreleg tibia of this species possess no spines, while the tarsi carry three rows of spines.
Adults are on the wing from May to June depending on the location. There is probably one generation per year. The caterpillars feed on such plants as bur oak (Quercus macrocarpa), Gambel oak (Q. gambeli), and willows (Salix).
Catocala delilah