Stilpon, Loew, 1859

Shamshev, Igor V. & Grootaert, Patrick, 2004, A Review Of The Genus Stilpon Loew, 1859 (Empidoidea: Hybotidae) From The Oriental Region, Raffles Bulletin of Zoology 52 (2), pp. 315-346 : 317

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 glandlike 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

Figures

Figs. 69-72. Stilpon paradoxus, new species, male. 69, mid leg, anterior view, 70, mid femur, posterior view, 71, apical part of hind tibia, dorsal view, 72, wing, dorsal view. Scale bar: 0.1 mm.

Figs. 80-84. Details of male abdomen, dorsal view. 80, Stilpon lek, new species, 81, Stilpon lekkwar, new species, 82, Stilpon trilobatus, new species, 83, Stilpon malayensis, new species, 84, Stilpon paradoxus, new species; T – tergite. Scale bar: 0.1 mm.

Figs. 73-75. Stilpon paradoxus, new species, male. 73, hypopygium, ventral view, 74, same, left lateral view, 75, phallus, dorsal view; hypd – hypandrium, rt epan lam – right epandrial lamella, rt sur – right surstylus, u lb – upper lobe of left surstylus. Scale bar: 0.1 mm.

Figs. 40-44. Stilpon khorngkeun, new species, male. 40, mid leg, anterior view, 41, wing, dorsal view, 42, hypopygium, ventral view, 43, upper lobe of left surstylus, dorsal view, 44, right surstylus, dorsal view. Scale bar: 0.1 mm.

Figs. 76-79. Stilpon yai, new species, male. 76, mid leg, anterior view, 77, hypopygium, ventral view, 78, upper lobe of left surstylus, dorsal view, 79, right epandrial lamella and right surstylus, dorsal view. Scale bar: 0.1 mm.

Figs. 5-10. Stilpon spinicercus, new species, male. 5, mid leg, anterior view, 6, wing, dorsal view, 7, hypopygium, ventral view, 8, upper lobe of left surstylus, dorsal view, 9, left cercus, right lateral view, 10, right surstylus, dorsal view; sur cm – surstylar comb. Scale bar: 0.1 mm.

Figs. 1-4. Stilpon monospinatus, new species, male. 1, mid leg, anterior view, 2, hypopygium, ventral view, 3, left surstylus, lateral view, 4, right surstylus, dorsal view; ap spn – apical spine, cerc – cerci, l lb – lower lobe of left surstylus, lft epand lam – left epandrial lamella, m lb – medial lobe of left surstylus, rt epand lam – right epandrial lamella, rt sur – right surstylus, sur cm – surstylar comb, u lb – upper lobe of left surstylus. Scale bar: 0.1 mm.

Figs. 60-63. Stilpon nhamdam, new species, male. 60, mid leg, anterior view, 61, hypopygium, ventral view, 62, upper lobe of left surstylus, dorsal view, 63, right surstylus, dorsal view. Scale bar: 0.1 mm.

Figs. 64-68. Stilpon trilobatus, new species, male. 64, mid leg, anterior view, 65, hypopygium, ventral view, 66, upper lobe of left surstylus, dorsal view, 67, left cercus and subepandrial sclerite, right lateral view, 68, right surstylus, dorsal view. Scale bar: 0.1 mm.

Figs. 54-59. Stilpon malayensis, new species, male. 54, mid leg, anterior view, 55, wing, dorsal view, 56, hypopygium, ventral view, 57, upper lobe of left surstylus, dorsal view, 58, left cercus and subepandrial sclerite, right lateral view, 59, right surstylus, dorsal view. Scale bar: 0.1 mm.

Figs. 15-19. Stilpon isaanensis, new species, male. 15, mid leg, anterior view, 16, hypopygium, ventral view, 17, left surstylus, lateral view, 18, upper lobe of left surstylus, dorsal view, 19, right surstylus, dorsal view; u lb – upper lobe of left surstylus. Scale bar: 0.1 mm.

Figs. 20-24. Stilpon laawae, new species, male. 20, mid leg, anterior view, 21, wing, dorsal view, 22, hypopygium, ventral view, 23, upper lobe of left surstylus, dorsal view, 24, right surstylus, dorsal view. Scale bar: 0.1 mm.

Figs.30-35.Stilpon seeluang, new species, male.30, mid leg, anterior view, 31, hind leg, anterior view, 32, wing, dorsal view, 33, hypopygium, ventral view, 34, upper lobe of left surstylus, dorsal view, 35, right surstylus, dorsal view. Scale bar: 0.1 mm.

Figs. 25-29. Stilpon nhamyaaw, new species, male. 25, mid leg, anterior view, 26, hypopygium, ventral view, 27, upper lobe of left surstylus, dorsal view, 28, left cercus and subepandrial sclerite, right lateral view, 29, right surstylus, dorsal view. Scale bar: 0.1 mm.

Figs. 36-39. Stilpon taksin, new species, male. 36, mid leg, anterior view, 37, hypopygium, ventral view, 38, upper lobe of left surstylus, dorsal view, 39, right surstylus, dorsal view. Scale bar: 0.1 mm.