Chen Ng(Pg61-69)

317

THE RAFFLES BULLETIN OF ZOOLOGY 2004

10 plate-like or desclerotized medially, positioned below

proctiger. Cercus elongate-ovate or broad-ovate. Spermatheca

membranous, sac-like.

Key to Stilpon species from the Oriental region

1. Male ........................................................................................ 2

–

Female (unknown in S. crassinervis, S. khorngkeun, S.

malayensis, S. monospinatus and S. yai) ...................... 18

2. Thorax wholly black to brown .............................................. 3

–

Thorax at least with yellow pleurae .................................... 12

3. Hind femur constricted and bent near middle. Hind tibia (Fig.

71) with long spur-like posterior apical comb. Abdominal

tergite 1 (Fig. 84) produced laterally into small corner-like

projection bearing 3 black spine-like bristles. Cerci (Fig.

73) completely fused into one large elongate oval lobe

.......................................................................... S. paradoxus

–

Hind femur evenly thickened toward middle. Hind tibia with

ordinary posterior apical comb. Abdominal tergite 1

unmodified. Cerci more or less separated, except base .... 4

4. Distance between apices of veins R2+3 and R4+5 nearly 1.5

times shorter than distance between apices of veins R1 and

R2+3. R4+5 strongly curved at apex (Fig. 41). Hind

tarsomere 1 brown ...................................... S. khorngkeun

–

Distance between apices of veins R2+3 and R4+5 longer than

distance between apices of veins R1 and R2+3. R4+5 evenly

arcuate or straight. Hind tarsomere 1 yellow ................. 5

5. R4+5 and M parallel and straight in apical part. Mid femur (Fig.

76) with 3 black antero- and 2 longer posteroventral spines

in basal half ............................................................... S. yai

–

R4+5 and M more or less divergent and arcuate in apical part.

Mid femur with less numerous black spines .................. 6

6. Fore tibia with 1 erect ventral bristle in apical part. Wing brown

before and beyond vein M .............................................. 7

–

Fore tibia clothed in ordinary setulae. Wing lacking prominent

pattern, more or less infuscate, usually somewhat deeper

along veins ....................................................................... 8

7. Mid femur (Fig. 5) with 1 black short ventral spine just beyond

middle, 3 long yellowish bristles in basal part and row of

anteroventral brownish spinules before middle. Abdomen

with gland-like structures between tergites 3-2 and 2-1. Left

surstylus with markedly developed surstylar comb (Fig. 8).

Left cercus (Fig. 9) divided, with 3 apical spines

....................................................................... S. spinicercus

–

Mid femur (Fig. 1) lacking black spines, only with 3-4 yellow

long ventral bristles in basal part. Abdomen without gland-

like structures. Left surstylus (Fig. 3) with hardly prominent

surstylar comb. Left cercus (Fig. 2) undivided, with 1 apical

spine ......................................................... S. monospinatus

8. Fore tibia brownish to brownish yellow. Mid femur brownish

at least in apical third ...................................................... 9

–

Fore tibia and mid femur yellow ......................................... 11

9. Mid femur (Fig. 60) with swelling in basal part, bearing 1 long

black anteroventral spine near middle. Hind femur brownish

in apical third ................................................ S. nhamdam

–

Mid femur slender, with different armature. Hind femur largely

brownish …….………….…………………………… 10

10. Mid femur (Fig. 64) bearing 2 black spines beyond middle. Hind

femur almost wholly brown, yellowish brown in extreme

base ................................................................ S. trilobatus

–

Mid femur with 3 posteroventral bristles in basal half. Hind

femur blackish in apical 3/4. Nepal ..... S. divergens Smith

11. Hind femur yellowish brown to brownish in apical 2/3. Halter

with contrastingly black knob and pale yellow stem.

Abdomen (Fig. 80) with gland-like structures between

tergites 4-3 and 3-2 .................................................. S. lek

–

Hind femur entirely yellow. Halter pale, knob with slight

brownish tinge. Abdomen (Fig. 81) with gland-like

structures between tergites 5-4, 4-3 and 3-2 ...... S. lekkwar

12. Scutum black, pleurae yellow. Mid femur (Fig. 54) with 2 short

dark posteroventral spines in basal 1/3 and 1 similar

anteroventral spine in apical 1/3. Abdomen (Fig. 83) with

gland-like structures between tergites 2-3 and 3-4. Upper

lobe of left surstylus (Fig. 57) with markedly developed

surstylar comb .............................................. S. malayensis

–

Scutum entirely yellow or with indistinct brownish spots near

postalar calli. Mid femur with pale basal bristles only.

Abdomen without gland-like structures. Upper lobe of left

surstylus lacking surstylar comb ................................... 13

13. Fore tibia and tarsomere 1 brown ........................................ 14

–

Fore tibia and tarsomere 1 yellow ....................................... 15

14. Postpronotal bristle long. Acrostichal and dorsocentral bristles

minute on prescutellar depression. Left cercus (Fig. 16) long,

right cercus undivided, short, broad, subrectangular

......................................................................... S. isaanensis

–

Postpronotal bristle hardly prominent. Acrostichal and

dorsocentral bristles quite long and distinct on prescutellar

depression. Left cercus (Fig. 22) very short, right cercus

consisting of two lobes ....................................... S. laawae

15. Vein R2+3 flattened at apex. Distance between apices of veins

R2+3 and R4+5 nearly 3.0 times longer than distance

between apices of veins R1 and R2+3 ...... S. crassinervis

–

Vein R2+3 ordinary. Distance between apices of veins R2+3

and R4+5 at most 2.0 times longer than distance between

apices of veins R1 and R2+3 ........................................ 16

16. Hind trochanter (Fig. 31) with 2 black ventral spines. Hind femur

with 3-4 fairly long anteroventral bristles in apical part.

Abdominal segment 8 with ordinary bristles. Left cercus

(Fig. 33) long, slender ...................................... S. seeluang

–

Hind trochanter lacking black spines. Hind femur with 5-6 fairly

long anteroventral bristles in apical part. Abdominal segment

8 with 2 very long bristles. Left cercus short .............. 17

17. Wing brownish before and beyond vein M. Left cercus (Figs.

26, 28) with 3 very long spines ................... S. nhamyaaw

–

Wing with indistinct pattern, more or less evenly infuscate. Left

cercus (Fig. 37) with ordinary bristles ................. S. taksin

18. Thorax black to brown ......................................................... 19

–

Thorax yellow ...................................................................... 24

19. Fore tibia brownish to brownish yellow ............................. 20

–

Fore tibia and mid femur yellow ......................................... 22

20. Hind femur brownish in apical 1/3 ........................ S. nhamdam

–

Hind femur largely brown to blackish ................................. 21

21. Hind femur blackish in apical 3/4 ............ S. divergens Smith

–

Hind femur almost wholly brown, yellowish brown in extreme

base ................................................................. S. trilobatus

22. Wing brown before and beyond vein M ............ S. spinicercus

–

Wing lacking prominent pattern, more or less infuscate ....... 23

23. Hind femur yellowish brown to brownish in apical 2/3

............................................................... S. lek / S. paradoxus

–

Hind femur entirely yellow ....................................... S. lekkwar

24. Postpronotal bristle long. Acrostichal and dorsocentral bristles

minute on prescutellar depression ................... S. isaanensis

-

Postpronotal bristle hardly prominent. Acrostichal and

dorsocentral bristles quite long and distinct and reaching

base of scutellum ................................................ S. laawae

25. Hind femur with 3-4 fairly long anteroventral bristles in apical

part ...................................................................... S. seeluang

–

Hind femur with 5-6 fairly long anteroventral bristles in apical

part .................................................................................. 26

26. Wing brownish before and beyond vein M ........... S. nhamyaaw

–

Wing with indistinct pattern, more or less evenly infuscate

................................................................................... S. taksin

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