Cosmopterix clemensella

Distinguished from similar Cosmopterix species by the combination of: forewing with three silvery white lines in basal area (subcostal, medial, subdorsal); yellow transverse fascia beyond middle with narrow dorsally bent apical protrusion; inner border of fascia formed by tubercular silver metallic fascia with blackish subcostal spot on outside; outer border formed by two tubercular silver metallic spots (dorsal spot about four times larger than costal spot and positioned more basally); short white costal streak from costal spot; and white apical line from apical protrusion to apex. The specific pattern of alternating dark and white antennal segments toward the apex also aids identification.

Small moth with forewing length approximately 4.9 mm. Head frons pale silvery grey with greenish and reddish reflections; vertex and neck tufts dark greyish brown with reddish gloss, lined white laterally and medially. Labial palpus with first segment very short and ochreous-white, second segment greyish brown with white longitudinal lines, third segment white with brown lateral lines. Antenna dark brown with interrupted white line from base to beyond one-half, followed by alternating dark brown and white segments toward apex. Thorax and tegulae dark greyish brown with reddish gloss; thorax with white medial line, tegulae lined white inwardly. Legs dark brown with reddish gloss; foreleg tibia and tarsal segments 1–3 and 5 with white lines; midleg and hindleg tibiae with white oblique basal and medial lines and white apical rings. Forewing dark greyish brown with reddish gloss, bearing three silvery white lines in basal area (subcostal, short thick medial, and narrower subdorsal), yellow transverse fascia beyond middle bordered by tubercular silver metallic fasciae with greenish reflections, and white apical line. Hindwing pale brownish grey. Abdomen dorsally yellow-ochreous, laterally pale grey with greenish reflection, ventrally white; anal tuft yellowish white.

Associated with wetlands and moist habitats supporting Carex sedges, the larval host plants. Specific habitat details beyond host plant association are not documented.

Canada: Manitoba, Ontario. United States: Maine south to mountains of southern North Carolina, most commonly recorded in New York and Ohio.

Adults fly from mid-May to early August.

Larvae feed on Carex species (sedges), mining the leaves. Adult feeding habits are not documented.

• Carex - larval host plantLarvae mine leaves

Larval stage mines leaves of Carex sedges. Pupation details not documented. Adults emerge and are active mid-May to early August.

Larvae are leaf miners, feeding internally within Carex leaves. Adult behavior beyond flight period is not documented.

Larval leaf mining may contribute to nutrient cycling in sedge-dominated wetlands. Specific ecological impacts are not documented.

No documented economic or cultural significance. Occasionally encountered by lepidopterists and naturalists in eastern North America.

• Other Cosmopterix speciesMany Cosmopterix species share similar size, metallic markings, and wing patterns. C. clemensella is distinguished by the specific configuration of its forewing fasciae and spots, particularly the yellow transverse fascia with dorsally bent apical protrusion and the relative sizes and positions of the silver metallic spots.

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life