Chen Ng(Pg61-69)

326

Shamshev & Grootaert: A review of the genus Stilpon from the Oriental region

10 uniformly sclerotized, not fused with ventroapical margin

of tergite 8. Cercus elongate oval, brownish yellow, clothed

in setulae of different length.

Measurements. – Body length 1.4-1.7 mm, wing length 0.9-

1.2 mm.

Etymology. – The name “nham” (spine in Thai) “yaaw” (long

in Thai) refers to the long spines on the male left cercus.

Phylogenetic relationships. – The relationships of this species

are unresolved beyond inclusion within the S.  seeluang

species group. However, the presence of 2 very long bristles

on the segment 8 of the male abdomen, the general structure

of the male terminalia and, especially, the greatly reduced

cerci suggest this species is allied with S. laawae,  S.

crassinervis, and S. nhamyaaw.

Distribution and seasonal occurrence. – Thailand. Known

from one locality in South Thailand. Recorded from the

beginning of April in a rain forest.

Stilpon seeluang, new species

(Figs. 30-35)

Material examined. – Holotype - male. THAILAND: Loei

province, Na Haeo, FIRS, near waterfall, sample n

°

 20013, 23

May.2000, coll. P. Grootaert (SWU).

Paratypes – 2 males, 7 females, same data as in holotype. Na

Haeo, FIRS, Malaise trap along a dry deciduous forest, coll.

Verapong Kiatsoonthorn & P. Grootaert: 1 male, 3-10

Sep.1999; 1 female, 10-17 Sep.1999; 1 male, 1 female, 8-

15.Oct.1999; 1 female, 4-27.Aug.2000;1 male, 3-10

Mar.2001; 1 male, 18-25 Mar.2001; 1 female, 25 Mar.2001-

1 Apr.2001; 1 female, 29 Apr.-6 May.2001; 1 female, 20-29

May.2001; 2 females, 29 May.-4 Jun.2001; 1 male, 17-24

Jun.2001; 1 female, 29-5.Aug.2001; 1 male, Na Haeo, Chang

Tok Waterfall, river bed, sample n

°

 23035, 17 Jun.2003, coll.

P. Grootaert (coll. SWU, RBINS & ZRC).

Diagnosis. – Species with yellow thorax. Hind femur in apical

2/3 and tarsomere 5 of all legs (usually more distinctly on

fore leg) brownish yellow; otherwise legs yellow. Male: mid

femur with 4 yellowish ventral bristles in basal part, hind

trochanter with 2 black spinules.

Description. – Male. Head black in ground-colour, with

minute ocellars and short inner verticals. Antenna yellow.

Postpedicel nearly 2.0 times longer than wide. Style about 5

times longer than postpedicel. Palpus pale yellow, small.

Thorax almost wholly yellow. Scutum entirely tomentose;

with 2 brownish, more or less rounded, distinctly bordered,

posterolateral spots including postalar calli; scutellar margins

and postnotum brownish; pleural sutures (especially in darker

specimens) brownish in varying extent. Postpronotal bristle

short, hardly prominent. Dorsocentrals in multiple rows,

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.

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THE RAFFLES BULLETIN OF ZOOLOGY 2004

complete posteriorly. Acrostichals 2-serial, complete

posteriorly.

Legs with colour pattern: hind femur in apical 2/3 and

tarsomere 5 of all legs (usually more distinctly on fore leg)

brownish yellow; otherwise legs yellow. Hind trochanter (Fig.

31) with 2 black spinules. Mid femur (Fig. 30) slender, with

1 long anterior subapical bristle, bearing 4 yellow to brownish

yellow, rather long, ventral bristles in basal half. Hind femur

(viewed laterally) evenly thickened toward middle, with 1

row of short (3-4 subapical bristles longer) anteroventral

bristles and some short dorsal bristles in basal part. Fore tibia

lacking prominent bristles. Mid tibia straight, rather slender,

lacking prominent ventral spinules. Hind tibia slightly arcuate,

with ventral setulae more distinctly prominent, posterior

apical comb unmodified.

Wing (Fig. 32) normally developed, covered with uniform

microtrichia; almost uniformly infuscate, somewhat deeper

along longitudinal veins. Costal vein with ordinary short

setulae on anterior margin. Vein R2+3 about 3 times longer

than Rs. Distance between apices of R2+3 and R4+5 1.2-1.3

times longer than distance between apices of R1 and R2+3.

R4+5 and M slightly divergent and evenly arcuate in apical

part. Halter with contrast black, elongate knob and pale yellow

stem.

Abdomen largely yellow, becoming darker toward

hypopygium, with segments (except segment 8) weakly

sclerotized and subequal in length, covered mostly with

scattered ordinary pale setulae, lacking gland-like structures.

Segments 1-2 unmodified. Segment 8 short, bearing

moderately long bristles.

Hypopygium (Fig. 33) dark brown, rather small. Hypandrium

with 2 long bristles in apical part. Epandrium completely

divided. Left epandrial lamella small, fused to hypandrium,

with 2 minute bristles in apical part. Left surstylus with upper

lobe (Fig. 34) divided; lower part small, lacking surstylar

comb, upper part elongate oval, with 1 short bristle. Right

surstylus (Fig. 35) with deep excision, lacking spines. Left

cercus unbranched, digitiform, lacking apical spines and long

bristles in basal part. Right cercus consisting of two short

lobes, lacking spines. Phallus short.

Female. In most respects identical to male. Palpus brownish

yellow. Hind trochanter lacking black spines. Terminalia

shortened. Segment 8 normally sclerotized. Proximal margin

of sternite 8 straight, without 2 anteriorly directed rods. Apex

of sternite 8 hinged and partially separated from base. Sternite

10 uniformly sclerotized, not fused with ventroapical margin

of tergite 8. Cercus elongate oval, brownish yellow, clothed

in setulae of different length.

Measurements. – Body length 1.4-1.7 mm, wing length 0.9-

1.0 mm.

Etymology. – “See” (colour in Thai) “luang” (yellow in Thai),

refers to the yellow colour of the thorax.

Phylogenetic relationships. – The relationships of this species

are unresolved beyond inclusion within the S.  seeluang

species group.

Distribution and seasonal occurrence. – Thailand. Only

known from Northeast Thailand, Loei province. Quite

common and recorded from March till October.

Stilpon taksin, new species

(Figs. 36-39)

Material examined. – Holotype - male, THAILAND: Songkhla

province, Ban Di Luang, beach forest, sample n

°

 97148,

30.Oct.1997, coll. P. Grootaert (coll. RBINS).

Paratypes – 1 male, 1 female, same data as in holotype

(RBINS).

Diagnosis. – Species with yellow thorax, most similar to S.

nhamyaaw. Differs primarily from its by indistinct pattern

of wing and setose left cercus of male terminalia.

Description. – Male. Head black in ground-colour, with

minute ocellars and hardly prominent inner verticals. Antenna

yellow. Postpedicel nearly 2.0 times longer than wide. Style

about 5 times longer than postpedicel. Palpus pale.

Thorax almost wholly yellow. Scutum with 2 indistinct

brownish spots near postalar calli, entirely tomentose.

Postpronotal bristle hardly prominent. Dorsocentrals in

multiple rows, complete posteriorly. Acrostichals 2-serial,

complete posteriorly.

Legs with colour pattern: hind femur with brownish tinge in

apical 3/4, otherwise legs yellow. Mid coxa with 2 brown

bristles on outer side. Hind trochanter lacking spinules. Mid

femur (Fig. 36) slender, with 4 long yellow bristles in basal

1/2. Hind femur (viewed laterally) more or less evenly

thickened, with row of anterodorsal bristles (5-6 subapical

longer) and some prominent anterior and dorsal bristles in

apical part. Fore tibia with ordinary setulae. Mid tibia lacking

ventral spinules. Hind tibia with some longer ventral setulae,

posterior apical comb unmodified.

Wing normally developed, covered with uniform

microtrichia; with indistinct pattern, more or less evenly

infuscate. Costal vein with short setulae along anterior margin.

Vein R2+3 about 1.5 times longer than Rs. Distance between

apices of R2+3 and R4+5 about 2 times longer than distance

between apices of R1 and R2+3. R4+5 and M almost parallel

and evenly arcuate in apical part. Halter with elongate, black

knob and pale stem.

Abdomen lacking gland-like structures. Segments 1-2 largely

pale yellow, remainder segments yellowish brown and

stronger sclerotized. Segment 8 with 2 very long and several

shorter bristles.

Hypopygium (Fig. 37) brown, rather small. Hypandrium with

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