Subfamily Pterophorinae - Five-lobed Plume Moths

Identification

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Guide to the Adults of the Tribes of Five-lobed Plume Moths (Pterophorinae)

Timothy Reichard, September 2023

All but two species of plume moths north of Mexico belong to the subfamily Pterophorinae and five of its tribes. Three tribes, Platyptiliini, Oxyptilini, and Oidaematophorini, are widespread in the United States and Canada and contain all but two genera and five species. The remaining genera and species belong to the tribes Marasmarchini and Pterophorini, which each have a limited distribution in the United States.

Lobe numbering. Forewing and hindwing lobes are numbered starting at the first along the wing costa and apex, increasing toward the inner margin. The forewing first lobe includes the costa and apex of the forewing, and the second lobe includes the inner margin and anal angle (if present) of the forewing. The hindwing first lobe includes the costa and apex of the hindwing, the third lobe includes the inner margin and anal angle (if present) of the hindwing, and the second lobe is in between. In resting postures of live five-lobed plume moths, the forewing first lobe, sometimes the forewing second lobe, and usually the short hindwing third lobe are visible. The hindwing first and second lobes are usually obscured by the forewing, and sometimes the forewing second lobe is folded and also obscured.

Lobe terms. In plume moth literature, many terms describing features of whole forewings and hindwings of moths in general are repeated for lobes of forewings and hindwings of plume moths. These terms include costa, outer margin, inner margin, anal angle, apex, basal area, medial area, terminal area, antemedial line, and postmedial line. For example, a forewing first lobe has its own costa (which coincides with the costa of the whole forewing) and its own inner margin (which is not part of the inner margin of the whole forewing), its own apex (same as the apex of the whole forewing) and its own anal angle (which is not the anal angle of the whole forewing), and so on. These terms are used for both whole wings and lobes in this guide.

The following key provides characters usually discernible in dorsal views of live adult specimens for identification to a tribe.

1a. Forewing first and second lobes both broad from the cleft base to a well developed outer margin, which includes an anal angle. Continue to 2.

1b. Forewing first lobe lacking an anal angle and outer margin, either with the breadth at cleft base tapering to an acute apex, or the whole lobe narrow and linear, hardly more than a vein between the fringes ending at an acute apex. Forewing second lobe of various shapes. Continue to 3.

2a. Hindwing third lobe dorsal fringe with or without a dark scale tooth. Forewing often with a costal triangular patch near the cleft base, sometimes without. When both the dark scale tooth and costal triangular patch are absent, the forewing second lobe dorsal fringe lacks dark spots, though one may be present at the anal angle. Distribution widespread. Platyptiliini

2b. Hindwing third lobe dorsal fringe without a dark scale tooth. Forewing without a costal triangular patch near the cleft base. Forewing second lobe dorsal fringe with dark spots between the cleft base and anal angle. One genus, Exelastis, distributed in the southeastern United States from Oklahoma and Texas to New Jersey and Florida. Marasmarchini

3a. Forewing ground color yellowish brown, tawny brown, or chocolate brown. Forewing second lobe either (1) with breadth, anal angle, and concave or sinuate outer margin, or (2) narrow and linear, hardly more than a vein between fringes to an acute apex. Forewing first lobe either with breadth and tapering to an acute apex, or narrow and linear. Hindwing third lobe dorsal fringe usually with a dark scale tooth, sometimes without. Oxyptilini

3b. Forewing ground color pure white, pale cream, pale yellow, pale tan, pale brown, or gray. Forewing second lobe with breadth and either (1) tapering to an acute apex without an outer margin or (2) with an oblique, well developed outer margin. Hindwing third lobe dorsal fringe without a dark scale tooth. Continue to 4.

4a. Forewing ground color grayish white and much of costa and fringes brown. Forewing second lobe narrow and tapering to an acute apex. One species, Singularia walsinghami, distributed in Colorado. Pterophorini

See Encyclopedia of Life for an image.

4b. Forewing ground color various. Forewing second lobe either tapering to an acute apex or with an oblique, well developed outer margin. Distribution widespread. Oidaematophorini