Thymelicus lineola

Common. Locally abundant.

One brood. Early June to mid-July

Open, dry, grassy areas. Meadows, pastures, forest openings, parks, roadsides, railways.

Wingspan: ¾″ to 1⅛″

Larva

The larva (caterpillar) is green, slender, and up to 1″ long.

There is a narrow, green, vertical stripe on the middle of the upper surface extending from the second thoracic segment across all abdominal segments. On each side of this mid-thoracic stripe is a pale stripe. There is also a whitish subdorsal stripe and a whitish lateral stripe. There is a white wax gland along the bottom of each side of abdominal sections 7 and 8.

The head is pale green with two wide, vertical, white stripes. The white stripes are sometimes bordered by narrower, dark reddish-brown stripes. There is no conscticed section (“neck”) between the head and the first thoracic segment.

Adult

The upper side of the both wings is mostly brigh, brassy orange. There is a thin black margin at the tip and a very thin black margin at the upper edge. The veins are slightly darkened near the margin. There is no black cell end bar. There is a very thin black stigma on forewing of the male. There is usually a thin vertical black line at the end of the forewing cell of the female. The upper wings are otherwise unmarked. The underside of the forewing is orange, that of the hindwing is grayish-brown. The underside of both wings has a powdery, whitish tint. The wingtips are rounded, not pointed.

The antennae are short, barred, reddish, and blunt-tipped.

Timothy (Phleum pratense), orchard grass (Dactylis glomerata ssp. glomerata), quackgrass (Elymus repens), rice cutgrass (Leersia oryzoides), and bluegrass (Poa spp.).

Flower nectar

The females lay a row of up to 30 eggs on a host plant. The eggs overwinter and hatch in the spring

This species was introduced into Ontario in 1910, and has been spreading about 20 miles per year.

Where found, this species is often explosively abundant.