Chen Ng(Pg61-69)

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

Wing normally developed, covered with uniform

microtrichia; almost uniformly infuscate, somewhat paler

along posterior margin. Costal vein with ordinary short setulae

on anterior margin. Distance between apices of veins R2+3

and R4+5 about 1.5 times longer than distance between apices

of veins R1 and R2+3. R4+5 and M divergent and evenly

arcuate in apical part. Halter pale, knob with slight brownish

tinge.

Abdomen with tergites 1-2 unmodified. Narrow gland-like

structures present between tergites 5-4, 4-3, and 3-2 (Fig. 81).

Tergites 3 and 4 shortened. Segment 8 with short bristles.

Hypopygium (Fig. 51) dark brown. Hypandrium with 2 long

bristles in apical part. Epandrium completely divided. Left

epandrial lamella small, fused to hypandrium, bearing 2 long

bristles in apical part. Left surstylus with upper lobe (Fig.

52) undivided, with markedly developed surstylar comb.

Right surstylus (Fig. 53) rather small, rounded apically,

lacking spines. Left cercus unbranched, elongate, digitiform,

lacking spines, with 1 long, spine-like, ventral bristle in

middle part and 3 thinner marginal bristles basally. Right

cercus consisting of two lobes, lacking spines; left lobe

slender, digitiform; right lobe small, rounded. Phallus long,

hair-like, curved.

Female. In most respects identical to male. Mid femur with

yellowish bristles in basal part, lacking black spines. Mid tibia

lacking ventral spinules. Abdomen lacking gland-like

structures. Terminalia elongate. Segment 8 stronger

sclerotized than preabdomen. Proximal margin of sternite 8

without 2 anteriorly directed rods. Apex of sternite 8 not

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 1.2-1.4 mm, wing length 0.8-

0.9 mm.

Etymology. – “Lek” (small) “kwar” (more) refers to the fact

that this species is even smaller than its sibling S. lek.

Phylogenetic relationships. – The relationships of this species

are unresolved beyond inclusion within the S. divergens

group.

Distribution and seasonal occurrence. – Thailand. Known

from one locality in Northeast Thailand only. Records from

April, May and June, but  one record also from September.

Stilpon malayensis, new species

(Figs. 54-59)

Material examined. – Holotype - male, SINGAPORE: Nee Soon,

swamp, sample n

°

 22054, 4 Dec.2002, coll. P. Grootaert (ZRC).

Diagnosis. – Species with brown mesoscutum and yellow

pleurae, otherwise similar to S. lek differing from it by

armature of male mid femur and details of male terminalia.

Figs. 50-53. Stilpon lekkwar, new species, male. 50, mid leg, anterior view, 51, hypopygium, ventral view, 52, upper lobe of left surstylus,

dorsal view, 53, right surstylus, dorsal view. Scale bar: 0.1 mm.

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

minute ocellars and long inner verticals. Antenna and palpus

brownish yellow. Postpedicel nearly 2.0 times longer than

wide. Style about 5 times longer than postpedicel.

Thorax with brown prothoracic sclerites and mesoscutum,

otherwise yellow. Scutum entirely tomentose. Postpronotal

bristle long, inclinate. Dorsocentrals in multiple rows,

complete posteriorly. Acrostichals 2-serial, complete

posteriorly.

Legs with colour pattern: mid femur in apical 1/3, hind femur

in apical 3/4, mid and hind tarsomere 5 brownish, fore

tarsomere 5 black, fore tibia and fore tarsomere 1 brownish

yellow. Mid coxa with 2 brown bristles on outer side. Hind

trochanter lacking spinules. Mid femur (Fig. 54) slender, with

2 short dark posteroventral spines in basal 1/3, 1 similar

anteroventral spine in apical 1/3 and yellow bristle in extreme

base. Hind femur (viewed laterally) more or less evenly

thickened, with row of anterodorsal bristles becoming longer

toward apex and row of prominent dorsal bristles. Fore tibia

lacking prominent ventral bristles. Mid tibia with rows of

ventral spinules and 1 longer subapical spinule. Hind tibia

unmodified.

Wing (Fig. 55) normally developed, covered with uniform

microtrichia; more or less uniformly, rather deep infuscate.

Costal vein with long setulae along anterior margin. Vein

R2+3 about 2.5 times longer than Rs. Distance between apices

of R2+3 and R4+5 1.2 times longer than distance between

apices of R1 and R2+3. R4+5 and M slightly divergent and

arcuate in apical part. Halter with elongate, contrast black

knob and pale stem.

Abdomen largely dirty yellow, bearing mostly scattered dark

setulae which are longer on pregenital segments, with all

tergites (except segment 8) subequal in length, tergites 1-2

unmodified. Gland-like structures present between tergites

4-3 and 3-2 (Fig. 83); posterior space consisting of three parts,

with lateral parts subglobular.

Hypopygium (Fig. 56) brown. Hypandrium with 2 strong

bristles in apical part. Epandrium completely divided. Left

epandrial lamella small, fused to hypandrium, with 2 fairly

long bristles in apical part. Left surstylus with upper lobe

(Fig. 57) undivided, with markedly developed surstylar comb.

Right surstylus (Fig. 59) moderately large, sublinear, with

excision on upper margin. Left cercus (Fig. 58) mostly long,

slender, divided into two lobes in apical part, lacking spines,

with 1 long ventral and 2 similar left marginal bristles in basal

part. Right cercus divided into lobes, lacking spines; left lobe

long, broad; right lobe hardly prominent, rounded at apex.

Phallus long, hair-like, curved.

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.

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