Key to species of Ypsolopha mucronella -group based on male genitalia
1. Phallus shorter than valva............................................................................. 2
- Phallus as long as or longer than valva................................................................... 4
2. Cornuti 1/3 length of phallus (Fig. 134).......................................................... Y. albistriata
- Cornuti half length of phallus........................................................................... 3
3. Cornuti composed of two rows of small thorns (Fig. 135)............................................. Y. strigosa
- Cornuti composed of two broad spines (Fig. 136).......................................... Y. paristrigosa sp. nov.
4. Valva triangular (Fig. 147).............................................................. Y. triangula sp. nov.
- Valva not triangular.................................................................................. 5
5. Valva widened apically................................................................................ 6
- Valva narrowed apically............................................................................... 8
6. Saccus obviously shorter than socius, phallus slightly longer than valva......................................... 7
- Saccus nearly as long as socius, phallus 1.3 times length of valva (Fig. 138)................................. Y. longa
7. Uncus triangular (Fig. 137)................................................................. Y. nigrofasciata
- Uncus subulate (Fig. 145)...................................................................... Y. yasudai
8. Coecum 2/5 length of phallus (Fig. 153)............................................................. Y. diana
- Coecum shorter than 1/3 length of phallus................................................................. 9
9. Uncus subulate..................................................................................... 10
- Uncus not subulate.................................................................................. 12
10. Phallus as long as valva, curved at middle................................................................ 11
- Phallus 1.2 times length of valva, nearly straight (Fig. 148)....................................... Y. aurea sp. nov.
11. Saccus 3/4 length of socius, ventral plate of gnathos narrowly tongue-shaped (Fig. 150).............. Y. chlorina sp. nov.
- Saccus 3/5 length of socius, ventral plate of gnathos broadly tongue-shaped (Fig. 140)............... Y. umbrina sp. nov.
12. Saccus sharp at apex................................................................................. 13
- Saccus round at apex................................................................................ 16
13. Uncus triangular, phallus curved at middle (Fig. 151)............................................... Y. nemorella
- Uncus degenerate, phallus nearly straight................................................................ 14
14. Valva ovate, saccus narrowed on basal portion............................................................ 15
- Valva elongate ovate, saccus parallel-sided (Fig. 144)........................................ Y. capitalba sp. nov.
15. Valva ovate, saccus constricted on basal 1/4, coecum relatively shorter (Fig. 142)........................ Y. ulingensis
15. Valva ovate, saccus constricted near basal 1/4, coecum relatively longer (Ponomarenko & Zinchenko 2013: Fig. 9).................................................................................................. Y. costibasella
16. Valva protruded at middle on dorsal margin, phallus straight (Fig. 146)................................... Y. falcella
- Valva straight along dorsal margin, phallus somewhat curved................................................ 17
17. Saccus as long as socius, phallus extremely slender (Fig. 152).................................... Y. bisticta sp. nov.
- Saccus shorter than socius, phallus relatively broad........................................................ 18
18. Phallus 1.4 times length of valva (Fig. 141)........................................................ Y. dentella
- Phallus as long as or slightly longer than valva............................................................ 19
19. Saccus 2/3 length of socius, phallus slightly longer than valva................................................ 20
- Saccus 5/7 length of socius, phallus as long as valva (Fig. 149)........................................ Y. blandella
20. Uncus triangular, ventral plate of gnathos nearly rectangular (Fig. 143)......................... Y. varidentella sp. nov.
- Uncus inconspicuous, ventral plate of gnathos ovate (Fig. 139)........................................... Y. saitoi