Tribe Oxyptilini

Identification

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Guide to the Adults of the Species of Tribe Oxyptilini in the Eastern United States and Canada

Includes species occurring from Ontario, Minnesota, and Louisiana to the Atlantic Coast

Timothy Reichard, Sept. 2023, updated July 2024

The following key uses adult characters that are often discernible in photo records with good photography.

1a. Forewing second lobe narrow and linear, hardly more than a vein between fringes and with an acute apex, lacking an anal angle and outer margin. Continue to 2.

1b. Forewing second lobe broader, the breadth continued to a well developed, concave or sinuate outer margin, including an anal angle. Continue to 6.

Note: Leptodeuterocopus neales, from subfamily Deuterocopinae, would key to here if mistaken for a species of the Oxyptilini. Unlike the species of Oxyptilini covered in this key, L. neales has reduced or absent longitudinal markings on the abdomen, has two or three dark scale teeth in the hindwing third lobe dorsal fringe, has antemedial areas of the first and second lobes paler than the rest of the forewing, and is known from North America north of Mexico only in peninsular Florida.

2a. Hindwing third lobe dorsal fringe without a dark scale tooth. Abdomen with two white, continuous subdorsal lines. Buckleria parvulus

2b. Hindwing third lobe dorsal fringe with a dark scale tooth. Abdomen with interrupted or disconnected, white subdorsal markings or a different pattern. Continue to 3.

3a. Antenna with alternating white and brown spots. Continue to 4.

3b. Antenna with longitudinal white and brown lines. Continue to 5.

4a. Hindwing third lobe dorsal fringe with a narrow, dark scale tooth at 2/3 length. Forewing first lobe with the medial area concolorous with the base of the wing, and with the costal fringe between the white postmedial line and apex having brown and white spots. Abdominal ground color and markings fawn-colored to whitish with low contrast, not conspicuously outlined in dark brown. Trichoptilus pygmaeus

See this iNaturalist record for a live adult image.

4b. Hindwing third lobe dorsal fringe with a wide, triangular, dark scale tooth near 2/3 length. Forewing first lobe with the medial area darker brown than the base of the wing, and with the costa white from the white postmedial line to the apex. Abdominal segments two, three, five, and six with white, diverging or parallel subdorsal lines or spots conspicuously outlined in dark brown. Dejongia lobidactylus

5a. Hindtibia with straight, longitudinal white stripes before the postmedial spurs. Forewing second lobe costal fringe with white scales finely intermixed with dark brown scales and with scales near the apex without a white stripe across the scale tips. Abdomen without a white middorsal line and with white subdorsal lines conspicuous on segments five through eight. Dejongia californicus

5b. Hindtibia with slightly oblique or helical, longitudinal white stripes before the postmedial spurs. Forewing second lobe costal fringe with white scales grouped into patches and with scales at the apex brown with a white stripe across the tips. Abdomen with a white middorsal line and with subdorsal lines inconspicuous on segments five through eight. Megalorhipida leucodactylus

6a. Abdominal segment four concolorous with brown ground color, without markings, appearing as an interruption of the series of markings on the other segments. Mesothorax between the tegulae also brown. Hindwing third lobe with dark scale tooth near the apex, well developed in both the dorsal and costal fringes. Continue to 7.

6b. Abdominal segment four marked with white, usually appearing similar to repeated markings on other segments, or has a different pattern contrasting with that of adjacent segments but not unmarked brown. Mesothorax with a white area connecting the white tegulae. Hindwing third lobe with a dark scale tooth well developed in the dorsal fringe either before or near the apex, sometimes also well developed into the costal fringe. Continue to 10.

7a. Forewing color lighter, tawny brown or yellowish brown, making the dark transverse dash or triangular patch before the cleft conspicuous. Metathorax without large, lateral white patches. Continue to 8.

Note: Good photography is essential to distinguish the following three species in photo records.

7b. Forewing color darker, chocolate brown, making the dark transverse dash before the cleft inconspicuous. Metathorax with large, white, lateral patches, not extending onto the tegulae. Geina tenuidactylus, Geina buscki

Note: These two species cannot be identified on sight or in photos of live adults. Photo record identifications stop at this species pair. Genital characters are necessary for single-species identification.

8a. Forewing with a contrasting, dark, triangular patch between the white discal spot and the cleft base, concolorous with the forewing first lobe medial area. Dorsal wing and abdominal color patterns more contrasting. Sphenarches ontario

Note: The location and size of the forewing dark triangular patch coincides well with a valley created in the membrane by the typical resting wing posture of a live adult of this and many similar species. Certain lighting conditions can cast a triangular shadow over the location of the triangular patch, which can confound identification, making a Geina periscelidactylus or G. sheppardi appear to be a Sphenarches ontario. Clues that the dark triangular area is a cast shadow rather than true scale pigment include: the triangle appearing too narrow on either forewing, the triangles on the left and right forewings having different shapes, the triangle appearing on only one forewing while the other has a transverse dash, and the triangle not matching the shade of the forewing first lobe medial area.

8b. Forewing with a contrasting, dark transverse line before the cleft base, not extended basad as a dark triangular patch. Dorsal wing and abdominal color patterns more or less contrasting. Geina periscelidactylus, Geina sheppardi. (Continue to 9.)

Note: The following two species are not always reliably identified on sight or in photo records, even with good photography. Genital characters or comparison of dorsal color patterns with curated specimens should be used for reliable identification. Some online biodiversity record web resources unjustifiably lump photo records of the two species into the Geina periscelidactylus taxon, creating a false impression that that species is much more common than Geina sheppardi. Both species are common and widespread across eastern North America.

9a. Forewing ground color a slightly brighter tawny brown. Forewing first lobe color patterns slightly more contrasting. Reliable determination by genital characters or comparison with curated specimens. Geina periscelidactylus

9b. Forewing ground color a slightly darker tawny brown. Forewing first lobe color patterns slightly less contrasting. Reliable determination by genital characters or comparison with curated specimens. Geina sheppardi

10a. Forewing ground color lighter, yellowish brown or tawny brown. Hindwing third lobe with the dark scale tooth developed more in the dorsal fringe than in the costal fringe. Continue to 11.

10b. Forewing ground color darker, chocolate brown. Hindwing third lobe with the dark scale tooth developed subequally into both the dorsal and costal fringes. Capperia

Note: The Capperia species form a complex of both described and undescribed species whose sight- and photo-identifiability have not been fully worked out.

11a. Forewing first lobe with the antemedial line distinctly more oblique than the postmedial line. Abdominal segments two and three with slightly diverging, white subdorsal lines, a pattern that continues onto segment four and subsequent segments with the subdorsal lines becoming more parallel. Oxyptilus delawaricus

11b. Forewing first lobe with the antemedial line no more oblique than the postmedial line. Abdominal segments two and three with strongly diverging, conspicuous, white subdorsal lines, which are contrastingly obscure on segment four, followed by conspicuous, white parallel subdorsal lines on the subsequent segments. Sphenarches anisodactylus