Cosmopterix bacata

Distinguished from similar Cosmopterix species by the combination of: four white lines in the forewing basal area (subcostal, medial, subdorsal, dorsal); broad dark yellow transverse fascia beyond middle of forewing; two tubercular silver to pale golden metallic spots (costal and dorsal) outwardly edging the transverse fascia, with dorsal spot approximately three times larger than costal spot and positioned closer to base; and white section of 14–17 segments at antennal apex. The specific arrangement and proportions of the metallic markings, particularly the relative sizes and positions of the costal and dorsal spots, are diagnostic.

Small moth with forewing length 3.9–5.0 mm. Head with frons shining bronze with greenish and reddish reflections; vertex and neck tufts shining dark brown with reddish gloss, lined white laterally and medially. Labial palpus with first segment very short and ochreous, second segment about three-quarters length of third and pale grey dorsally with dark brown ventral and apical areas, third segment white with dark brown lateral lines. Antenna shining dark brown with short white line at base and white section of 14–17 segments at apex. Thorax and tegulae shining dark brown with reddish gloss, thorax with white median line. Legs shining dark brown with reddish gloss; femora of midleg and hindleg golden brown; foreleg with white line on tibia and tarsal segments one, two, and five. Forewing shining dark brown with reddish gloss, bearing four white lines in basal area: subcostal from one-tenth to one-quarter gradually bending from costa, very short medial ending just beyond subcostal, subdorsal about three times length of medial, and short narrow dorsal from beyond base to one-fifth. Broad dark yellow transverse fascia beyond middle, narrowing toward dorsum, inwardly edged by broad tubercular silver to pale golden metallic fascia, outwardly edged by two tubercular silver to pale golden metallic costal and dorsal spots (dorsal spot about three times size of costal and closer to base), both narrowly edged dark brown inwardly; costal streak white; silvery white apical line from middle of apical area, often broadly interrupted. Cilia dark brown around apex, paler on dorsum toward base. Hindwing shining dark greyish brown with pale brown cilia. Abdomen dorsally shining dark brown, ventrally shining grey with segments banded white posteriorly; anal tuft ochreous-grey.

Southeastern United States: from northern Florida to southwest Alabama, south to central Florida and Louisiana.

Adults active from late April to mid-July.

• small moth
• metallic markings
• southeastern US endemic
• spring-summer flight

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