| 1 | Forewing with distinct brown streak from disc to apex |
| | 21.0-34.0mm. Late May to September. Forewing in male broad with rounded apex, in female elongate and very acute, termen concave; both sexes ochreous yellow with dark brown dots and streaks. See couplets 6, 8 and 9. |
| - | Forewing without distinct brown streak from disc to apex |
| | Forewing sometimes with a cloudy brown streak from disc to costa before apex. |
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| 2 (1) | Forewing with ochreous whitish costal streak from base to apex |
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| - | Forewing without pale costal streak |
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| 3 (2) | Forewing with vein 10 originating from common stalk of veins 8 and 9; without dark brown dots |
| | 22.0-35.0mm. June to early September. Forewing relatively broad with rounded apex, in female elongate and acute; both sexes ochreous. |
| - | Forewing with vein 10 originating from cell, veins 8 and 9 stalked; often with dark brown dots. |
| | The forms tripartita Dufrane and intermedia Dufrane with pale costal streak on forewing, not rare. See couplets 4, 8 and 9. |
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| 4 (2) | Males |
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| - | Females |
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| 5 (4) | Hindwing greyish white with postmedian and terminal bands of short, dark streaks |
| | 25.0-33.0mm. June to early September. Forewing rather broad; apex blunt; grey, ochreous mixed with dark dots and streaks; the form nigristiellus Popescu-Gorj, Olaru & Draghia with long longitudinal line is rare in males. For female see couplet 9. |
| - | Hindwing white without series of dark streaks |
| | Form uniformata Dufrane. See couplets 4, 6 and 9. |
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| 6 (4) | Larger species, 34.0-48.0mm. Forewing with termen slightly convex |
| | June to early September. Forewing more elongate; ochreous brown, sometimes almost unmarked, but often with dark dots and streaks; the form nigristiellus Popescu-Gorj et al. (see couplet 8) is common in females. |
| - | Smaller species, 24.0-34.0mm. Forewing with termen distinctly concave |
| | Form uniformata Dufrane. See couplets 4, 6 and 8. |
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