Cosmopterix clandestinella

Adults can be distinguished from similar Cosmopterix species by the combination of: three short silver metallic streaks of equal length at one-fifth of the forewing; a shining dark yellow transverse fascia beyond one-half bordered by silver metallic markings; and a dorsal spot three times the size of the costal spot. The interrupted white line on the antenna extending from base to beyond one-half, followed by specific segment patterning (six brown, six white, eight brown, six white, one brownish), provides additional diagnostic characters. The larval stage is identifiable by the three brilliant wine-red longitudinal stripes on a light green body at maturity.

Associated with habitats supporting the host plant Dichanthelium clandestinum. Specific habitat details beyond host plant association are not documented.

Eastern United States: Massachusetts, southern Ohio, Virginia, North Carolina, and Michigan. Vermont records also confirmed.

Two generations annually. Adults emerge from late May to early June, and again from late July through August. Michigan specimens represent the second generation, with mines collected in August and adults emerging the following May.

Larvae feed on Dichanthelium clandestinum (Poaceae).

• Dichanthelium clandestinum - larval host plantLarvae mine the leaves of this grass species.

Two generations per year. Larvae mine leaves of Dichanthelium clandestinum, creating irregular longitudinal blotch mines with frass ejected at one end. At maturity, the larva cuts a circular piece from the mine epidermis, bends it lengthwise, and uses it as a cocoon—behavior analogous to the genus Cycloplasis. Adults emerge in late May to early June (first generation) and late July to August (second generation).

Larval leaf-mining behavior: creates irregular longitudinal blotch mines with frass ejected at one end. Cocoon construction involves cutting a circular piece of epidermis from the mine, bending it lengthwise, and using it as a protective structure.

• Cosmopterix speciesCosmopterix clandestinella can be distinguished from congeners by the specific pattern of three equal-length silver metallic streaks at one-fifth of the forewing, the dark yellow transverse fascia, and the relative sizes of the costal and dorsal spots (dorsal spot three times larger than costal). Antennal segment patterning also differs among species.
• Cycloplasis speciesLarval cocoon construction behavior is analogous—both genera cut circular epidermal pieces from mines and bend them lengthwise for cocoons—though Cycloplasis belongs to a different family (Gracillariidae) and adults differ substantially in appearance.

• leaf miner
• grass-feeding
• bivoltine
• eastern North America

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