Key to Elbenia species (males only)

(Figs. 2–4)

Nineteen species is known from this Southeast Asian genus. The male of E. dyscrita Karny, E. makilingae Hebard and E. manilensis Pictet are however not known. The females for most species of the genus are not known and as such, omitted from the key.

1. Distribution: Philippines ................................................................................ 2

- Distribution: Sundaland (Malay Peninsula, Borneo, Sumatra and Java)........................................... 3

2. Tenth abdominal segment with apical lobes rounded at apex (Fig. 2 A). Cerci shorter, not surpassing apex of subgenital plate (Fig. 2 A). Subgenital plate bilobed, elongated and recurved towards abdomen, distal part internally serrated (Fig. 2 A)......................................................................................... E. serraticauda Hebard

- Tenth abdominal segment with apical lobes acute at apex (Fig. 2 B). Cerci longer, surpassing apex of subgenital plate. Subgenital plate rectangular and short, not serrated..................................... E. modesta Brunner von Wattenwyl

3. Tenth abdominal segment with two apical lobe elongated and process-like, often spinose (Figs. 3 A–3E)................. 4

- Tenth abdominal segment with or without apical lobes, when present, not process-like (Figs. 3 F– 3I).................... 8

4. Tenth abdominal segment with apical lobe projecting near lateral margins, forming a wide-roundly excision in the middle (Figs. 3 A, 3B). Subgenital plate roundly emarginated only at tip, forming small rounded lobes at apex (Figs. 4 A, 4B)...... 5

- Tenth abdominal segment with apical lobe projecting medially, narrowly excised in between (Figs. 3 C–3E). Subgenital plate more deeply excised, forming elongated lobes............................................................... 6

5. Cerci shorter, distally curved dorsad (Fig. 2 C). Subgenital plate with apical lobes rounded at apex, with short internal process, not densely covered with bristles (Figs. 2 C, 4A).............................................. E. bispinosa Karny

- Cerci longer, distally curved dorsad, then curved posteriorly (Fig. 2 D). Subgenital plate with apical lobes more angular at apex, without short internal process, densely covered with bristles (Figs. 2 D, 4B).......................... E. javanica Karny

6. Tenth abdominal segment with apical lobe finger-shaped, truncated apically (Fig. 3 C). Subgenital plate with incised margin sinuous................................................................................. E. digitata Karny

- Tenth abdominal segment with apical lobe spine-like, acute apically (Figs. 3 D, 3E). Subgenital plate with incised margin not sinuous.............................................................................................. 7

7. Cerci longer, about twice the length of apical lobes; strongly curved inward, apex simple (Fig. 3 D). Subgenital plate with apical lobes parallel and straight; apex with inner margin not denticulated............................ E. nigrosignata Stål

- Cerci shorter, less than twice the length of apical lobes; gently curved inward, apex pointed outward (Fig. 3 E). Subgenital plate with apical lobes narrow and sinuous (and crossing each other) at distal half; apex with inner margin denticulated................................................................................................ E. robinsoni Karny

8. Tenth abdominal segment with distinct apical lobes short and truncated (Figs. 3 F– 3I)................................ 9

- Tenth abdominal segment without apical lobe or with apical lobe fused.......................................... 13

9. Tenth abdominal tergite with apical lobes angularly excised in the middle; lobes diverging from one another............ 10

- Tenth abdominal tergite with apical lobes roundly excised in the middle; lobes not diverging from one another (Fig. 3 F)......................................................................................... E. pendleburyi Karny

10. Tenth abdominal tergite with apical lobes bifurcated distally (Figs. 3 G, 3H)....................................... 11

- Tenth abdominal tergite with apical lobes not bifurcated distally (Fig. 3 I)........................................ 12

11. Tenth abdominal tergite with apical lobes bifurcated into an inner sharp process and outer rectangular plate (Fig. 3 G). Subgenital plate with lobes smooth along inner margin............................. E. appendiculata Brunner von Wattenwyl

- Tenth abdominal tergite with apical lobes bifurcated into two sharp, black processes (Fig. 3 H). Subgenital plate with lobes serrated along inner margin................................................................. E. jacobsonii Karny

12. Tenth abdominal tergite with apical lobes obtusely blunt distally when viewed dorsally (Fig. 3 I); distad turned inwards and compressed when viewed laterally; with three teeth along apical margin when viewed laterally.......... E. smedleyi Karny

- Tenth abdominal tergite with apical lobes rectangular, truncated distally (Fig. 5 E); simple when viewed laterally (Fig. 5 F); without tooth along apical margin when viewed laterally (Fig. 5 F).................................... E. fraser sp. n.

13. Tenth abdominal segment with apical lobes fused or appearing fused along internal margins......................... 14

- Tenth abdominal segment without apical lobe.............................................................. 15

14. Tenth abdominal segment with apical lobes along inner margins fused to form a wider than long triangular apex. Subgenital plate with lobes curved dorsad and then recurved towards abdomen (Fig. 2 E)............ E. tenera Brunner von Wattenwyl

- Tenth abdominal segment with apical lobes short and finger-like, converging to fuse along inner margins at apex. Subgenital plate with lobes bent dorsad abruptly in the middle; bent horizontally backward apically (Fig. 2 F)............................................................................................. E. brevixipha Brunner von Wattenwyl

15. Subgenital plate not triangular, deeply split into two long and narrow cylindrical lobes, surpassing cerci; distal part curved dorsad and anteriorly (Fig. 2 G)............................................................... E. loliifolia (Haan)

- Subgenital plate triangular, without apical lobe; posteriorly margin excised or emarginated medially (Figs. 4 C, 4D)....... 16

16. Tenth abdominal segment with apical margin truncated. Subgenital plate acutely triangular, long and slender; sharply and more deeply excised at apex (Fig. 4 C)............................................................... E. fissa Karny

- Tenth abdominal segment with apical margin slightly emarginated behind. Subgenital plate long but broader; more bluntly emarginated at apex (Fig. 4 D)................................................................. E. fusca Karny