Key to species of Ypsolopha vittella -group based on female genitalia

(exclusive of Y. asperella, Y. albula sp. nov., Y. longisaccata sp. nov. and Y. horridella)

1. Signum with one transverse ridge....................................................................... 2

- Signum with two transverse ridges...................................................................... 5

2. Lamella postvaginalis Y-shaped (Fig. 161)................................................... Y. flavida sp. nov.

- Lamella postvaginalis V-shaped......................................................................... 3

3. Ductus bursae sclerotized on posterior 4/5 (Fig. 172)........................................... purpurata sp. nov.

- Ductus bursae membranous............................................................................ 4

4. Ductus bursae twisted near corpus bursae, signum narrowed posteriorly (Fig. 171)................. Y. latiuscula sp. nov.

- Ductus bursae not twisted near corpus bursae, signum ovate (Fig. 160)....................... Y. flaviterminata sp. nov.

5. Ductus bursae broadened to corpus bursae, not distinctly separated from corpus bursae............................. 6

- Ductus bursae narrow, distinctly separable from corpus bursae................................................ 8

6. Ductus bursae sclerotized entirely (Fig. 155)......................................................... Y. vittella

- Ductus bursae membranous............................................................................ 7

7. Signum 3/5 length of corpus bursae (Fig. 169)............................................ Y. mucronulata sp. nov.

- Signum 1/2 length of corpus bursae (Fig. 170).............................................. Y. bicostata sp. nov.

8. Intersegmental membrane between papilla analis and 8th abdominal segment longer than abdomen (Fig. 156)... Y. japonica

- Intersegmental membrane between papilla analis and 8th abdominal segment as long as or shorter than abdomen........ 9

9. Ductus bursae shorter than corpus bursae................................................................ 10

- Ductus bursae longer than corpus bursae................................................................. 12

10. Ductus bursae granulous before inception of ductus seminalis, signum rounded on anterior half (Fig. 158)..... Y. hebeiensis

- Ductus bursae granulous from inception of ductus seminalis to corpus bursae, signum rhombic on anterior half......... 11

11. Signum trapezoid posteriorly (Fig. 157)......................................................... Y. amoenella

- Signum triangular posteriorly (Fig. 166)................................................. Y. scabrella (Linnaeus)

12. Lamella postvaginalis convex on posterior margin (Fig. 167)........................................... Y. acerella

- Lamella postvaginalis concave on posterior margin........................................................ 13

13. Corpus bursae rounded............................................................................... 14

- Corpus bursae long ovate or triangular.................................................................. 16

14. Ductus bursae twisted near corpus bursae (Fig. 162)................................................. Y. parallela

- Ductus bursae straight, not twisted near corpus bursae...................................................... 15

15. Lamella postvaginalis V-shaped, ductus bursae granulous on posterior 1/3 (Fig. 165)............. Y. fascimaculata sp. nov.

- Lamella postvaginalis Y-shaped, ductus bursae entirely smooth (Fig. 163)............................ Y. sarmaticella

16. Corpus bursae triangular (Fig. 159)............................................................ Y. leuconotella

- Corpus bursae long ovate............................................................................. 17

17. Ductus bursae 1.7 times length of corpus bursae (Fig. 168).............................................. Y. yangi

- Ductus bursae 1.25 times length of corpus bursae (Fig. 164)....................................... Y. parenthesella