Moths of North Carolina
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12 NC Records

Cosmopterix clemensella Stainton, 1860 - Clemens' Cosmopterix Moth

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Superfamily: Gelechioidea Family: CosmopterigidaeSubfamily: CosmopteriginaeTribe: [Cosmopterigini]P3 Number: 420373.00 MONA Number: 1493.00
Comments: Cosmopterix is a very large genus of small, colorful moths that are found on every continent except Antarctica. There are 31 species that are currently recognized in North America, and all are leafminers.
Field Guide Descriptions: Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Hodges (1978)Technical Description, Immature Stages: Eiseman, 2019                                                                                 
Adult Markings: The following description focuses on forewing and antenna patterning, and is based on a more detailed description presented by Koster (2010). The antenna is shining dark brown with an interrupted white line from the base to beyond one-half, a short section at the base that is often uninterrupted, followed towards the apex by approximately ten dark brown segments, nine white segments (sometimes broken by two dark brown segments into two white bars, which is commonly the case in North Carolina specimens), ten dark brown segments, and seven white segments at the apex. The vertex and dorsal thorax region have two lateral and a medial whitish line. The forewing is dark grayish brown with three silvery white lines in the basal area. These consist of 1) a subcostal line from the base to one-quarter of the wing length that slightly bends from the costa distally, 2) a very short but thick medial line above the fold that ends at the distal end of the subcostal, and 3) a subdorsal line that is twice as long as the medial line and narrower. This line starts just before the distal end of the medial line. A yellow transverse fascia occurs just beyond the middle of the wing that narrows towards the dorsum and has a narrow and dorsally bent apical protrusion. The fascia is bordered on the inner edge by a tubercular silver metallic fascia that does not reach the costa, and by a small blackish subcostal spot. The outer edge of the transverse facia is bordered by two tubercular silver metallic costal and dorsal spots. The dorsal spot is about four times as large as the costal spot and positioned more towards the base. Both spots are irregularly lined with dark grayish brown on the inside. A short white costal streak extends from the costal spot to the costa. A shining white apical line extends from the apical protrusion to the apex. The cilia are dark grayish brown, but paler towards the dorsum. The hindwing is pale brownish gray, and the cilia are grayish brown. The abdomen is yellow-ochreous dorsally. Koster (2010) noted that the most diagnostic combination of traits for this species is the very short medial line on the forewing, the outer dorsal spot that is four times as large as the outer costal spot, and the yellow-ochreous abdomen. As with other Cosmopterix, antenna patterning is helpful in identifying species.
Forewing Length: 4.9 mm (Koster, 2010)
Adult Structural Features: Male genitalia. The right brachium of the uncus is short and stout, and has a large triangular apical part. It gradually tapers distally, and the apex is lengthened, narrow, and rounded. The left branchium is less than one half the length of the right brachium and gradually tapers. The apex is rounded. The valva has an upper margin that is strongly concave, a lower margin that is slightly concave, and a caudal margin that is straight. The anellus lobes are large, slightly bent in the middle, and strongly widening in the apical half. The apex is blunt. The aedeagus has a wide, bottle-shaped, bulbous part that strongly narrows distally to about one-third of the width. The basal part is short, and about one-third the length of the bulbous part. The lateral lobes are large and rounded distally.

Female genitalia. The posterior edge of sternite VII is concave with a convex section in the middle. This convex middle section is also shallowly concave in its middle. The sterigma is very large and broad, and tapers at both ends. The ostium bursae is round, with two small and round protrusions laterally, and a crescent-shaped sclerotization ventrally. The ductus bursae is about two-thirds of the length of the corpus bursae, and with an inner sclerite where it enters the latter. The corpus bursae is long and elongated, and the signa has two round plates with a central vertical rim.
Adult ID Requirements: Identifiable from photos showing hindwings, abdomen, or other specialized views [e.g., frons, palps, antennae, undersides].
Immatures and Development: The larvae mine the leaves of sedges. Larvae from eggs that are laid in late summer or early fall begin mining in the fall and complete development in overwintering leaves during the spring or early summer. The larvae make long, irregular, semitransparent galleries that run parallel with the veins. Frass is deposited externally at or near the end of the mine, and individuals will frequently abandon one mine to form a new one (Eiseman, 2019). The final instar pupates within the mine. Many southern populations appear to have a second brood in late summer.
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Cosmopterix clemensella occurs across southern Canada from Albert to Nova Scotia. In the US it occurs from the northeastern states southward and westward to Illinois, Kentucky, and North Carolina. As of 2022, we have only a few scattered records from the Coastal Plain to the western Piedmont and Blue Ridge.
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ‚Č• 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

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