Key to species of Ypsolopha vittella -group based on external characters

1. Forewing brown, with purple metallic shine (Fig. 25)......................................... Y. purpurata sp. nov.

- Forewing not brown, without purple metallic shine......................................................... 2

2. Forewing with a broad streak along dorsum............................................................... 3

- Forewing without such broad streak.................................................................... 12

3. Streak along dorsum darker than ground colour of forewing.................................................. 4

- Streak along dorsum paler than ground colour of forewing................................................... 10

4. Streak with upper margin yellowish white................................................................. 5

- Streak without differently colored upper margin............................................................ 6

5. Forewing with several rows of dark brown scales (Fig. 22).................................. Y. mucronulata sp. nov.

- Forewing without such rows as above (Fig. 23)............................................. Y. bicostata sp. nov.

6. Forewing with apex protruded triangularly (Fig. 21)................................................ Y. horridella

- Forewing with apex rounded........................................................................... 7

7. Forewing with several rows of ocherous brown scales on distal 2/3 (Fig. 20)................................ Y. yangi

- Forewing without such scales as above................................................................... 8

8. Forewing with R4 and R5 very short stalked (Fig. 57), cell with a dark brown strip at end (Fig. 6)............ Y. amoenella

- Forewing with R4 and R5 separated, cell without dark brown strip at end......................................... 9

9. Forewing with a longitudinal interrupted median dark brown strip on distal half (Fig. 4)...................... Y. vittella

- Forewing without such strip as above (Fig. 5)...................................................... Y. japonica

10. Forewing yellowish brown mixed with dark brown on distal 1/3 (Fig. 9)...................... Y. flaviterminata sp. nov.

- Forewing grayish white or grayish brown on distal 1/3...................................................... 11

11. Streak on dorsum of forewing white (Fig. 8)..................................................... Y. leuconotella

- Streak on dorsum of forewing grayish white (Fig. 7)............................................... Y. hebeiensis

12. Forewing uniformly pale yellow except having a brown dot at 2/3 of fold (Fig. 10)................... Y. flavida sp. nov.

- Forewing not uniformly coloured, with fine markings...................................................... 13

13. Forewing with a triangular yellowish brown patch ranging from dorsal 1/4 to 3/4 (Fig. 11).................. Y. asperella

- Forewing without such a patch......................................................................... 14

14. Forewing with two parallel stripes...................................................................... 15

- Forewing without such stripes......................................................................... 16

15. Thorax yellowish brown (Fig. 12), forewing with R4 and R5 separated (Fig. 63)........................... Y. parallela

- Thorax yellowish white (Fig. 13), forewing with R4 and R5 short stalked (Fig. 64)...................... Y. sarmaticella

16. Forewing with several rows of small dots................................................................ 17

- Forewing without such dots........................................................................... 18

17. Forewing with a white strip from end of cell to apex (Fig. 16)................................ Y. longisaccata sp. nov.

- Forewing without white strip (Fig. 17)................................................. Y. fascimaculata sp. nov.

18. Forewing with erect scales............................................................................ 19

- Forewing without erect scales......................................................................... 20

19. Forewing with white and brown strips along veins (Fig. 18)........................................... Y. scabrella

- Forewing without strips as above (Fig. 19)......................................................... Y. acerella

20. Wing expanse over 23.0 mm, apex protruded triangularly (Fig. 24).............................. Y. latiuscula sp. nov.

- Wing expanse equal to or less than 20.0 mm, apex rounded.................................................. 21

21. Forewing with grayish brown or ocherous brown strips along veins (Fig. 15)......................... Y. albula sp. nov.

- Forewing without strips along veins (Fig. 14)................................................... Y. parenthesella