Key to world genera of Sialidae

(after Liu et al. (2015a) and Martins et al. (accepted); adults of † Sharasialis Ponomarenko, 2012 are unknown)

Taxa that contain only extinct species are preceded by a dagger (†); taxa that contain both extant and extinct species are followed by “(+ †)”; taxa that contain only extant species are unannotated.

1. Forewing: MA 2-branched (Liu et al. 2015a: fig. 8a–c) ................................................................... 2

‒ Forewing: MA simple (Liu et al. 2015a: fig. 8g ‒i) ........................................................................... 6

2. Forewing: costal area only weakly broadened proximally (ca 1‒1.5× as wide as distal costal area) (Liu et al. 2015a: fig. 8a–b); MA1 and MA2 ca 0.8–1.5× as long as MP1 and MP2 (length from its origin to its end on posterior wing margin) (Liu et al. 2015a: fig. 8a–b) ......................................... 3

‒ Forewing: costal area distinctly broadened proximally (ca 2× as wide as distal costal area) (Liu et al. 2015a: fig. 8l); MA1 and MA2 ca 2× as long as MP1 and MP2 (length from its origin to its end on posterior wing margin) (Liu et al. 2015a: fig. 8l) .......................................................................... ..................................................................................... † Proindosialis van der Weele, 1909 (France)

3. Forewing: ra-rp crossveins all more or less perpendicular to RA and RP (Liu et al. 2015a: fig. 8a, g); male abdomen: 10 th gonocoxites present (as a pair of weakly sclerotized lobes) (Liu et al. 2015a: fig. 9a‒d) ........................................................................................................................................... 4

‒ Forewing: 1‒2 ra-rp crossveins inwardly oblique (i.e., proximal angle with RA >> distal angle with RA) (Liu et al. 2015a: Fig. 8b–c); male abdomen: 10 th gonocoxites absent (Liu et al. 2015a: figs 10a‒d, 11a‒d) ............................................................................................................................. 5

4. Forewing: medio-cubital space with two crossveins (Liu et al. 2015a: figs 1a, 8a); CuA 2-branched (Liu et al. 2015a: figs 1a, 8a) ................................................. Austrosialis Tillyard, 1919 (Australia)

‒ Forewing: medio-cubital space with one crossvein (Liu et al. 2015a: fig. 8j); CuA 3-branched (Liu et al. 2015a: fig. 8j) ..................................... † Dobbertinia Handlirsch in Schröder, 1920 (Germany)

5. Forewing: costal space with proximal subcostal veinlets not strongly oblique (Liu et al. 2015a: fig. 8b); male abdomen: tergite 9 without a digitiform posteroventral process (Liu et al. 2015a: fig. 10c); ectoproct with spiniform setae ventrally (Liu et al. 2015a: fig. 10d); female abdomen: gonocoxites 8 fused as a single sclerite (Liu et al. 2015a: fig. 10f); gonapophyses 8 subtriangular in ventral view (Liu et al. 2015a: fig. 10f) .............................................................................................. .................................................................................................. Stenosialis Tillyard, 1919 (Australia)

‒ Forewing: costal space with (most) proximal subcostal veinlets strongly oblique (Liu et al. 2015a: fig. 8c); male abdomen: tergite 9 with a digitiform posteroventral process (Liu et al. 2015a: fig. 11c); ectoproct without spiniform setae ventrally (Liu et al. 2015a: fig. 11c); female abdomen: gonocoxites 8 paired (Liu et al. 2015a: fig. 11f); gonapophyses 8 broadly shield-like in ventral view (Liu et al. 2015a: fig. 11f) ................................................................................................................... ............................................... Leptosialis Esben-Petersen, 1920 part (L. necopinata) (South Africa)

6. Fore and hindwing: RP 4-branched (Liu et al. 2015a: fig. 8e, g); male abdomen: 9 th gonocoxites widely separated (Liu et al. 2015a: fig. 16b, d) ................................................................................ 7

‒ Fore and hindwing: RP ≥ 5-branched (Liu et al. 2015a: fig. 8h–i); male abdomen: 9 th gonocoxites closely adjacent medially (Liu et al. 2015a: fig. 18h, l) ..................................................................... .......................................................... Sialis Latreille, 1802 (+†) (Asia, †Europe and North America)

7. Forewing: MP simple (Liu et al. 2015a: figs 1c, 8e) ........................................................................ 8

‒ Forewing: MP 2-branched (Liu et al. 2015a: fig. 8f–g) .................................................................. 10

8. Fore and hindwing: RP basal branch simple (Liu et al. 2015a: fig. 1c) ............................................. ................................................... Leptosialis Esben-Petersen, 1920 part (L. africana) (South Africa)

‒ Fore and hindwing: RP basal branch 2-branched (Liu et al. 2015a: fig. 8e–f) ................................. 9

9. Hindwing: intramedial space with 2 crossveins (Liu et al. 2015a: fig. 8e); male abdomen: sternite 9 without an elongate median lobe (Liu et al. 2015a: fig. 13b–c); ectoproct without an elongate and weakly sclerotized projection (Liu et al. 2015a: fig. 13a, c) .............................................................. ............................................. Indosialis Lestage, 1927 (+†) (Southern Asia, east Pakistan, † Turkey)

‒ Hindwing: intramedial space with one crossvein (Liu et al. 2015a: fig. 8k); male abdomen: sternite 9 with an elongate median lobe (Nel et al. 2002: fig. 5); ectoproct with an elongate and weakly sclerotized projection (Nel et al. 2002: fig. 5) .............................† Eosialis Nel et al., 2002 (France)

10. Male abdomen: gonostyli 9 absent (Liu et al. 2015a: fig. 14c–d); gonocoxites 11 not fused laterally with ectoproct (Liu et al. 2015a: fig. 14c–d); female abdomen: gonocoxites 8 without longitudinal median incision (Liu et al. 2015a: fig. 15d) .....................................................................................11

‒ Male abdomen: gonostyli 9 present (Figs 3‒5); gonocoxites 11 fused laterally with ectoproct (Figs 3‒5); female abdomen: gonocoxites 8 with longitudinal median incision (Fig. 6C– D) .......... .............................................................................................................. Caribesialis gen. nov. (Cuba)

11. Male abdomen: gonocoxites 9 large, not subtriangular (Liu et al. 2015a: fig. 14c); ectoprocts free (Liu et al. 2015a: fig. 14c–d); female abdomen: tergite 9 in lateral view with posterodorsal margin not projected, dorsal region straight (Liu et al. 2015a: fig. 15c); gonapophyses 8 large and plate-like in ventral view (Liu et al. 2015a: fig. 15b, d) ................................................................................. 12

‒ Male abdomen: gonocoxites 9 small, subtriangular (Liu et al. 2015a: fig. 16c); ectoprocts fused sagittally and closely surrounding the anus (Liu et al. 2015a: fig. 16c–d); female abdomen: tergite 9 in lateral view with posterodorsal margin projected into a convex curvature (Liu et al. 2015a: fig. 16e); gonapophyses 8 small and subtriangular in ventral view (Liu et al. 2015a: fig. 16f) ......... ............................................................................................... Protosialis van der Weele, 1909 (USA)

12. Forewing: crossvein 1r-m arising from MA (generally from its base) (Liu et al. 2015a: fig. 8f); base of CuP clearly distant from A1 base (Liu et al. 2015a: fig. 8e); male abdomen: median processes of 11 th gonocoxites directed posteroventrad (Liu et al. 2015a: fig. 14c–d) ......................................... 13

‒ Forewing: crossvein 1r-m arising from stem of M (Liu et al. 2015a: fig. 8d); base of CuP close to A1 base (Liu et al. 2015a: fig. 8d); male abdomen: median processes of 11 th gonocoxites directed posterodorsad (Liu et al. 2015a: fig. 12c–d) ......................... Haplosialis Navás, 1927 (Madagascar)

13. Forewing: costal veinlets absent on pterostigma region (Huang et al. 2016: fig. 2a); crossvein 1a2– a3 absent (Huang et al. 2016: fig. 2a); male abdomen: ectoproct with a slender, weakly sclerotized projection (Huang et al. 2016: fig. 2b) .................... † Haplosialodes Huang et al., 2016 (Myanmar)

‒ Forewing: costal veinlets present on pterostigma region (Liu et al. 2015a: fig. 8f); crossvein 1a2–a3 present (Liu et al. 2015a: fig. 8f); male abdomen: ectoproct without a slender, weakly sclerotized projection (Liu et al. 2015a: fig. 14c) ................................................................................................. ................................................ Ilyobius Enderlein, 1910 (+†) (Mexico, Central and South America)