greater black-letter dart

not listed

NNR - Unranked

not listed

Greater black-letter dart is a common, medium-sized moth. Adults are ¾″ to 13 ⁄16″ (20 mm to 21 mm) in length, with a wingspan of 19 ⁄16″.

The forewing is long and moderately narrow. On the male it is reddish-brown, on the female it is bluish-gray. The base of the wing on both sexes is purplish-gray. The line separating the basal area and median area (antemedial line) is scalloped. In the upper median area, a large, triangular, straw-colored spot (orbicular spot) widens toward the leading edge of the wing. In the lower median area, a large, kidney-shaped spot (reniform spot) is burnt orange to purplish-gray with a thin black outline. There are also conspicuous dark spots, including a black basal dash, a median bar, and a subapical patch. The terminal area of the wing is noticeably darker on males, much less so on females.

The hindwing on the male is whitish-gray at the base, becoming darker gray as it approaches the margin, with slightly darker veins. The hindwing of the female is similar but darker.

The head and thorax are same color as the forewing. The thin line on the thorax just behind the head (collar) is pale brownish-yellow. The antennae are slender and thread-like.

The caterpillars are smooth and about 1½″ in length. They are usually brown but are sometimes green or gray. Three stripes on the upper (dorsal) side of the abdomen (the middorsal and subdorsal stripes) are thin and inconspicuous. On gray and brown caterpillars there are usually dark slanting spots on each abdominal segment in the subdorsal area. A pale horizontal stripe (subspiracular stripe) on each side of the abdomen dips below the breathing opening (spiracle) on the eighth abdominal segment (A8) and continues onto the leg-like appendage (proleg) on A10. The spiracles are white to tan with a thin black outline. The ground color of the abdomen is darker above the subspiracular stripe, paler below. Each proleg has a number of minute hooklets (crochets) that allow the caterpillar to hold onto vegetation. The proleg on A3 has about 25 crochets. A dark bar on each side of the head runs over the top of the head (vertex) and continues to the to the side of the triangle (frons).

Total length: ¾″ to 13 ⁄16″

Wingspan: 19 ⁄16″

Forests and woodlands

Two generations, May to September

The caterpillars burrow into the ground where they spend the day. They come out at night to feed on vegetation within a meter of the ground.

They overwinter as late stage (instar) larvae.

Grasses, forbs, and low-growing woody plants; and apple, maple, currant, and pear. Possibly also agricultural crops, including barley, clover, corn, and tobacco.

Flower nectar

Sources

21, 24, 27, 29, 30, 71, 75.

Common

In 1980, setaceous Hebrew character (Xestia c-nigrum) was separated from greater black-letter dart (Xestia dolosa). Before that, they were considered one species. In 1998, J. Donald Lafontaine suggested that the two species are ecologically separated, with X. dolosa inhabiting moderately moist (mesic) woodlands, and X. c-nigrum inhabiting disturbed and grassy landscapes, agricultural crops, fields, and gardens. According to Lafontaine, only X. c-nigrum is an agricultural pest.

Location: Pennington Co MN