Eucosma bilineana

Appearance

From the original description by Kerfoot in The Canadian Entomologist (1907), Vol. 39, pages 54-55:

"Forewing pale clayish ochre, with two horizontal black lines, one from base to middle, and one above it from middle to apex, the latter divided and more or less diffused on its outer half. Head rough, dull brown in front, shading into ochreish-brown on top. Palpi flattened, ovate, scales neither compressed nor loosely laid, apical
joint exposed above, but hidden below by projecting tuft from second joint; colour pale ochreish, darker on outer sides and below, apex brown.

Antennae ochreish, lightly ciliated in both male and female. Thorax whitish-ochreous, shading into dark brownish-ochreous anteriorly. Abdomen and legs cinereous, tarsi and tibia marked and dotted with dark brown. Fore wing pale, terracotta or clayish-ochre ; palest along dorsal margin, and overlaid with a deeper ochreous shade along costa and outer third. A narrow black line through middle of wing from just beyond
base, nearly to end of cell, where it diminishes to a hair streak and follows vein ii nearly to angle. Above the outer end of the thickened part of this line, at two-thirds length of cell, another wide line begins, and continues to end of cell, where a narrow spur from its up edge continues in termen just below apex ; the inner end of this line is somewhat clavate, beyond its outer end, below the apical spur, is a cloud of whitish, dark brown and ochreous scales, between veins v and vii, and over the latter line is a second spur of black scales, but much broken. The costal fold is nearly half the length of wing, closely appressed at base, but rolled over at its outer end ; colour, ground colour, but of a more sombre hue ; costa beyond fold pale ochreous, with five evenly-spaced black dots, below these are five or six other black dots, not evenly spaced. On the dorsal margin are about the same number of black dots, closer together about the middle. A row of similar dots along the termen, and a (cw others scattered over the wing, several in the ocellic space, one below outer end
of second horizontal line, and a faint line below and paralleling the inner half of the inner line. Cilia grayish-fuscous, paler basally and mottled with darker fuscous scales. Hind wing above and below smoky-ochreous, cilia paler. Underside fore wing smoky-fuscous, paler along costa, where the dark costal dots are repeated. Cilia paler. The above description is from an average male. In other specimens the intensity of the dark lines and dots are less or greater. In one male specimen the dark markings are nearly obsolete, leaving only a faint basal and faint outer line, no dots at all. While in another the dark marks are intensified and the whole outer upper half of wing is clouded with dark scales; the outer end of the outer line divides into three distinct lines or spurs.

I have but one female, which differs considerably from the male. All of the head, palpi, and thorax colouring is much darker. The forewing is a dull brown, overlaid on lower half below cell with whitish-gray scales, a line of these same scales are above and join the internal black line, and above this is a parallel line of gray-white scales, all the veins beyond the cell are overlaid with the same, and the intervening spaces rather closely
speckled with them. The outer black line with its spurs is obsolete, but three or four black dots remain on outer half of costa, and a cluster of black dots on the ocellic space, of which four are in a vertical row along termen and three or four before them."

Naming

Eucosma bilineana Kearfott, 1907

Distribution

Alberta southeast through eastern Nebraska and southern Manitoba and on to Ohio.

Food

Larval host is Jerusalem artichoke (Helianthus tuberosus).