1 | Forewing ochreous white to brown or dark brownish grey; first cross-line obsolete or absent |
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- | Forewing more or less suffused greyish, blackish or black; first cross-line present and distinct |
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2 () | Forewing whitish ochreous; second cross-line slightly sinuate or straight |
| 14.0-19.0mm. Late May to August. Forewings with first cross-line and sub-terminal line obscure; orbicular, claviform and discal spot small dot-like or elongate. |
- | Forewing dark brownish grey; second cross-line angularly bent above middle |
| This is the form scotica White with darker forewing; markings indistinct or absent. See couplet 22. |
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3 (1) | Forewing with second cross-line strongly sinuate inwards on fold and outwards in disc, indentation at an angle of about 30° to dorsum |
| 18.0-20.0mm. Late June to early August. Forewing blackish, slightly olive-tinged with white, dark-edged cross-lines; discal mark black, x-shaped, claviform spot black, dot-like and orbicular pale, outlined black. Hindwing with greyish discal mark. |
- | Forewing with second cross-line less strongly sinuate, indentation at an angle of 60°-90° to dorsum |
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4 (3) | Forewing with discal spot absorbed in black quadrate costal blotch at two-thirds. Hindwing with dark discal marks, more distinct on underside |
| 15.0-19.0mm. June to early August. Forewing whitish, sometimes darker, with brownish black markings; cross-lines white, dark edged; orbicular and claviform spots absorbed in blackish irroration distal to first cross-line. |
- | Forewing with discal spot separate, not absorbed in dark costal blotch. Hindwing without dark discal mark |
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5 (4) | Forewing with orbicular spot light-centred (pale grey, ochreous or pale brown), more or less completely ringed dark brown, blackish or black |
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- | Forewing with orbicular spot represented by a blackish dot or streak, not light-centred |
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6 (5) | Forewing with dark edging of discal mark 8-shaped, orbicular spot round |
| 16.0-22.0mm. May to early August. Forewing with basal and median area predominantly white; first and second cross-line white, black-edged towards the median area; dark brown colour sometimes reduced, occasionally the wing is pure white, also the dark mark |
- | Forewing with dark edging of discal mark x-shaped, occasionally tending towards an 8-shape; orbicular spot oval or elongate |
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7 (6) | Forewing with sub-terminal cross-line indistinct or absent |
| 16.5-25.0mm. Late May to early September. Forewing rather uniform pale grey, slightly brownish tinged; cross-lines whitish, dark-edged inwardly, first curved, second angularly bent above middle; orbicular spot indistinctly outlined dark, claviform spot bl |
- | Forewing with sub-terminal cross-line distinct |
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8 (7) | Forewing broad, length costa about 2.5 times width at three-quarters; terminal cilia conspicuously barred white and black |
| 21.0-25.0mm. June to early August. Forewing heavily irrorated blackish; first cross-line zigzagging, second sinuate above middle. There is little variation, forms with darker and also paler median space are known, the latter named f. bifascialis Tu |
- | Forewing narrow, length costa about 3 times width wing at three quarters, terminal cilia indistinctly barred basally |
| 17.0-23.0mm. Early May to early September. Forewing whitish, sprinkled grey; first cross-line zigzagging, second strongly angulated above middle. Very variable. Dark forms are described, viz. a dark and smaller form with clear pale markings (f. atomali |
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9 (5) | Forewing with costal third of second cross-line, if extended with an imaginary line, reaching to middle of termen. Generally larger species, 18.0-20.0mm |
| Late June to early October. Forewing with blackish tinge predominantly, particularly in fresh specimens; cross-lines whitish, dark-edged, first zigzagging, second angulate-sinuate; spots black; there is little variation, occasionally the median area is di |
- | Forewing with costal third of second cross-line, if extended with an imaginary line, reaching termen near dorsum. Generally smaller species, 16.0-20.0mm |
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10 (9) | Forewing with white sub-terminal cross-line interrupted near middle and diverted into tornus by black clouding; second cross-line weakly curved above middle. Hindwing whitish grey, darker near termen |
| 16.0-20.0mm. Late May to early August. Forewing whitish, sprinkled blackish, basal and terminal areas dark; first cross-line zigzagging; both spots dot-like, black; specimens with dark median area are common, occasionally forewing strongly tinged ochreous |
- | Forewing with white sub-terminal cross-line not interrupted near middle; second cross-line in costal third indentated. Hindwing pale grey, brownish grey in distal half |
| 16.0-20.0mm. June to early September. Forewing grey, suffused blackish; first cross-line followed by a broad blackish band; cross-lines white, dark-edged, first curved, second fine; both spots dot-like, black, usually absorbed in the blackish band. Rather |
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