Key to Idaea species of the Baikal region

1. Wings with purple and yellow portions, and one dark transverse line (Fig. 20C); ground colour of both wings is commonly purplish-red with large yellow discal spots and wide yellow terminal stripe. In male genitalia (Figs. 40N–40P) uncus bifid, valva without modifications, extremely narrow, widened distally; vesica with small cornutus. In female genitalia (Fig. 50C) ductus weakly sclerotized, with longitudinal furrows.................................. I. muricata (Hufnagel, 1767)

- Coloration and pattern of wing different................................................................... 2

2. Ground colour of wings brightly rufous, dark yellow or deep brown with contrasting transverse lines or without them...... 3

- Ground colour of wings pale yellow, grayish or whitish with thin or not contrasting transverse lines.................... 6

3. Wings different shades of rufous or yellow, in male genitalia valva with either process on ventral margin, or narrowed medially; in female genitalia corpus bursae not spherical, or if spherical then only its posterior part covered with tiny spines........ 4

- Wings different shades of brown (in fresh samples deep reddish-brown or brightly ochreous), with slightly sinuous dark transverse lines (2–3 lines on forewing and 2 lines on hindwing). In male genitalia (Figs. 40H–40J) valva with straight ventral margin, not narrowed medially; in female genitalia (Fig. 50A) ductus sclerotized, corpus bursae spherical, membranous, entirely covered with tiny spines.......................................................... I. falckii (Hedemann, 1879)

4. Wings bright yellow or pale orange, with dark, almost transverse lines (3 lines on forewing and 2 lines on hindwing), fringes blackish; hindwing without discal dot. In male genitalia (Figs. 40K–40M) vesica with no cornuti, juxta with pair of long processes, valva simple, without projections on their margins; in female genitalia (Fig. 50B) ostium comparatively wide.................................................................. I. aureolaria ([Denis & Schiffermüller], 1775)

- Wings rufous or rusty brown, with not contrasting, often weakly distinct wavy lines; hindwing with discal dot; in male genitalia vesica with cornutus, juxta without processes, ventral margin of valva with projection; in female genitalia ostium comparatively narrow.............................................................................................. 5

5. In male genitalia (Figs. 40A –0C) valva with small projection on ventral margin; saccus more elongated than in I. serpentata; cornutus very large, bent at angle of almost 90°, apex of cornutus protrudes beyond apex of aedeagus. In female genitalia (Fig. 49J) corpus bursae elongated, more than 2 mm .................................... I. dohlmanni (Hedemann, 1881)

- In male genitalia (Figs. 40F, 40G) valva with process on ventral margin; saccus shorter than in I. dohlmanni, rounded; cornutus smaller than in I. dohlmanni, less curved, its apex does not protrude beyond apex of aedeagus. In female genitalia corpus bursae short, its length is about 1 mm (Fig. 49I)........................................... I. serpentata (Hufnagel, 1767)

6. In male genitalia phallos extremely long: more than 5 mm, coiled, vesica with more than 20 thorn-shaped cornuti and long filiform sclerite (Figs. 41L, 41M); in female genitalia ductus seminalis very long, coiled, with numerous sclerotized spicules (Fig. 51A)................................................................ I. straminata (Borkhausen, 1794)

- In male genitalia phallos considerably shorter than 5 mm, number of cornuti varies from 1 to 3; in female genitalia ductus seminalis not coiled................................................................................... 7

7. Males.............................................................................................. 8

- Females............................................................................................ 13

7. Costal margin of valva with dentiform projection in distal half.................................................. 8

- Costal margin of valva without processes.................................................................. 9

8. Apex of aedeagus with pair of horn-like sclerotized appendages; saccus comparatively wide; valva narrowed distally, with sharp notch distad of costal projection (Figs. 41F, 41G)........................... I. nitidata (Herrich-Schäffer, 1861)

- Apex of aedeagus without horn-like appendages, vesica with one hook-shaped cornutus; saccus narrow; valva gradually narrowed toward tip, without sharp notch distad of costal projection (Figs. 41C–41E)............................................................................................... I. pallidata ([Denis & Schiffermüller], 1775)

9. Valvae distinctly asymmetric, right one with more elongated and bent apex; aedeagus curved, S-shaped (Figs. 39M, 39N); terminal area of forewing often with 3–4 distinct dark brown spots near tornus.............. I. dimidiata (Hufnagel, 1767)

- Valvae symmetrical, their apices not elongated and not bent; aedeagus relatively straight, occasionally with dorsally bent coecum............................................................................................ 10

10. Vesica with 1 spiniform or rod-shaped or laminiform cornutus, or latter is absent; tegumen without sclerotized dentate processes under uncus......................................................................................... 11

- Vesica with 3 or more cornuti; tegumen with pair strongly sclerotized dentate processes under uncus (Figs. 41J, 41K).................................................................................... I. aversata (Linnaeus, 1758)

11. Valva tapered distally; vesica with straight long cornutus (Figs. 42A–42C); wings dark gray (Fig. 22C)............................................................................................. I. descitaria (Christoph, 1893)

- Valva almost not tapered distally, its apex roundish; cornutus different; wings not gray: pale yellow to grayish-ochreous... 12

12. Valva with 3–5 small strongly sclerotized spines on inner surface near ventral margin and apex; vesica with robust, S-shaped cornutus; coecum of aedeagus bent dorsally (Figs. 41H, 41I)............................. I. biselata (Hufnagel, 1767)

- Valva without small sclerotized spines on its inner surface; vesica bears thin broad irregular plate with more sclerotized lateral edges; coecum of aedeagus not bent dorsally (Figs. 41A, 41B).......................... I. sylvestraria (Hübner, 1799)

13. Anterior part of corpus bursae with membranous appendix (Fig. 50D).................................. I. sylvestraria

- Anterior part of corpus bursae without appendix............................................................ 14

14. Ductus bursae with spherical membranous appendix (Fig. 50G).......................................... I. biselata

- Ductus bursae without spherical membranous appendix...................................................... 15

15. Posterior part of corpus bursae twisted; ductus bursae narrow and long, well sclerotized (Fig. 50H)............ I. aversata

- Posterior part of corpus bursae not twisted................................................................ 16

16. Posterior part of ductus bursae with broad sclerotized plate near ostium (Fig. 50F); signa fill only anterior part of corpus bursae, also forming separate narrow strip of spines in central part of corpus bursae................................ I. nitidata

- Posterior part of ductus bursae without broad sclerotized plate near ostium; signa fill almost all inner surface of corpus bursae or one of its lateral side............................................................................... 17

17. Corpus bursae elongated, one of its lateral side or / and its anterior end membranous, without signa (Fig. 51C); ductus seminalis arises from posterior part of corpus bursae; ductus bursae rather uniformly sclerotized; wings dark gray........ I. descitaria

- Corpus bursae more or less spherical, entirely filled with signa; ductus seminalis different; ductus bursae sclerotized nonuniformly: just its posterior part or only central (lateral sides of ductus bursae membranous); coloration of wings different .................................................................................................. 18

18. Ductus bursae rather broad, with longitudinal sclerotization in central part, its posterior part without spines (Fig. 50E); ductus seminalis arises from large membranous appendix in posterior part of corpus bursae........................ I. pallidata

- Ductus bursae narrow, almost entirely membranous, only its posterior part filled with tiny thin spines (Fig. 51B); corpus bursae without appendix in posterior part; terminal area of forewing often with 3–4 distinct dark brown spots near tornus.................................................................................................... I. dimidiata

Key to Timandra species of the Baikal region

1. Forewing without apical streak; medial line of both wings pale brownish grey; wings with strong brown or grey brown suffusion, wing pattern and discal spots very diffuse; frons strongly convex. In male genitalia (Figs. 48J, 48K) costa not furcate, valva with broad ventral subterminal projection; apex of aedeagus straight, without process. In female genitalia antrum T-shaped, with strongly sclerotized lateral projections (Fig. 55E)................................ T. rectistrigaria (Eversmann, 1851)

- Forewing with reddish apical streak usually merging into more oblique medial line; wing pattern more distinct, often contrasted; medial line of both wings reddish, rose or brownish grey; frons more or less protruded. In male genitalia sclerites of valva partially cleft, costa furcate; apex of aedeagus curved or with process. In female genitalia antrum different.............. 2

2. Frons strongly protruded. In male genitalia (Figs. 49C, 49D) margins of socii not spinose; costa of valva with ventro-anally directed finger-like process; sacculus long: more than ¾ of length of costa; apex of aedeagus curved, without process. In female genitalia (Fig. 56B) ostium with large trapezoid sclerite covered with stout scales............... T. paralias (Prout, 1935)

- Frons slightly protruded. In male genitalia costa of valva with dorsally directed process; sacculus short (about ½ of length of costa), sub-triangular, with long narrow sclerotized process; in female genitalia ductus bursae comparatively broad, mostly sclerotized........................................................................................... 3

3. Ground colour of wings whitish or greyish with dense dark-grey dusting; oblique medial line usually weak and thin (Fig. 30B). In male genitalia (Figs. 48L–48N) socii shallowly wrinkled, with short teeth; in female genitalia posterior margin of sternite A8 straight or slightly concave, appendix bursae angle towards corpus bursae about 120° (Fig. 55F)................................................................................................... T. griseata W.Petersen, 1902

- Ground colour of wings yellowish, with weak rose tinge especially pronounced outward from medial line; dusting sparse, pale yellowish brown; oblique medial line usually wider, more distinct than in T. griseata (Fig. 30C). In male genitalia (Figs. 49A, 49B) socii deeply dentate; in female genitalia posterior margin of sternite A8 strongly concave, appendix bursae angle towards corpus bursae about 100° (Fig. 56A).................................................. T. recompta (Prout, 1930)