1 | Frons and vertex bright yellow, thorax purplish black |
| 12.0-14.0mm. May and June. Forewing unicolorous purplish black except plical and second stigmata which are black with raised scales. Labial palpus black and yellow. |
- | Frons and vertex concolorous with thorax |
| |
|
2 (1) | Forewing predominantly orange or yellow |
| |
- | Forewing predominantly dark brown |
| Paler areas of forewing sometimes partly suffused with ochreous yellow scales. |
|
3 (2) | Forewing yellow, whitish towards base. Vertex, frons and labial palpus shining white; antenna pale grey, indistinctly annulated darker |
| 14.0-18.0mm. July (in Central Europe also in August). Forewing with dark brown costal streak and two large brown spots, at two-fifth and at tornus respectively. |
- | Forewing bright orange. Vertex, frons and labial palpus brassy blackish brown; antenna blackish brown, white apically |
| |
|
4 (3) | Forewing bordered dark brown, with streak along costa comparatively narrow, not connected with dark brown dorsal streak |
| 10.0-13.0mm. Late June to early August. Forewing with three larger and two smaller tubercular silvery spots. |
- | Forewing bordered dark brown, with streak along costa comparatively broad and connected with brown dorsal streak at one-third, forming a broad dark brown fascia. |
| 11.0-13.0mm. July (June to August in Great Britain). Forewing with pattern of silvery spots similar to that of the preceding species. |
|
5 (2) | Frons and vertex shining dark greyish brown |
| 9.0-12.0mm. Early June to early August (abroad). Forewing with whitish markings reduced, pale costal spot at three quarters rather distinct. |
- | Frons and vertex white or whitish, more or less suffused with dark brown |
| |
|
6 (5) | Forewing with pale colour creamy, pale dorsal streak at least in basal area partly suffused with ochreous yellow |
| 11.0-12.5mm. Early June to mid August. Melanistic forms occur. |
- | Forewing with pale colour pure white, without ochreous yellow suffusion |
| 10.0-11.5mm. Late May to early July. |
|