Chen Ng(Pg61-69)

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

present between tergites 4-3 and 3-2 (Fig. 82), with posterior

space broader, consisting of three parts.

Hypopygium (Fig. 65) brown, large. Hypandrium with 2 long

bristles in apical part. Epandrium completely divided. Left

epandrial lamella small, fused to hypandrium, with 2 long

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

66) undivided, with markedly developed surstylar comb.

Right surstylus (Fig. 68) moderately large, broadened in basal

part, more or less rounded at apex, lacking spines. Left cercus

(Fig. 67) unbranched, slender, somewhat broadened at apex,

very long, lacking spines, with 1 long ventral and 2 similar

marginal bristles basally. Right cercus consisting of two lobes,

lacking spines; left lobe slender, very long; right lobe slender,

nearly 2 times shorter than left one. Phallus long, hair-like,

curved.

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

row of yellowish bristles. Hind femur slender. Postabdomen

elongate, strongly sclerotized, concolorous with thorax, tergite

8 distinctly separated from sternite 8. 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, clothed in setulae of different

length.

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

1.2 mm.

Etymology. – The name of this species refers to the trilobed

posterior abdominal gland.

Phylogenetic relationships. – The relationships of this species

are unresolved beyond inclusion within the S. divergens

group.

Distribution and seasonal occurrence. – Thailand. A species

with a wide distribution: Northeast to South Thailand (Loei,

Krabi and Songkhla provinces). Records in the North from

May, October in the South.

The species of uncertain group position

Two species described below are difficult to include within

some of the species groups proposed. Certainly, they could

be ascribed to as separate groups with a single species

included. However, we consider that it would be prematurely.

Undoubtedly, many new species of Stilpon will be described

in the future and additional intermediate forms may yet be

found.

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.

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THE RAFFLES BULLETIN OF ZOOLOGY 2004

Both species cannot be included in the S. varipes species

group primarily because they share, like all other species

known from the Old Word, entirely tomentose scutum and

complete rows of acrostichal setulae. These species can be

distinguished from the species of the S. graminum group by

setose male cerci. The species of the S. seeluang group have

yellow thorax, small male terminalia, unmodified abdominal

segments and different structure of the male terminalia.

Stilpon paradoxus, new species

(Figs. 69-75)

Material examined. – Holotype - male, THAILAND: Loei

province, Na Haeo, riverbanks in gallery forest at FIRS, sample n

°

2020, 24 May.2000, coll. P. Grootaert (SWU).

Paratypes – 6 males, 6 females, same data as in holotype; 2

males, 5 females, Na Haeo, sample n

°

 99016, 10 Feb.1999,

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

Diagnosis. – Species with black brown thorax, differing from

all other species from Oriental region by a set of unique

characters of male, including constriction in middle hind

femur, spur-like posterior apical comb on hind tibia, modified

abdominal tergites 1-2, completely fused cerci; female

habitually very similar to S. lek but with shortened terminalia.

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

minute anterior and posterior ocellars and long cruciate inner

verticals. Antenna brownish yellow (in darker specimens

postpedicel and style darker). Postpedicel nearly 2.0 times

longer than wide. Style about 5 times longer than postpedicel.

Palpus pale.

Thorax wholly black brown. Scutum entirely tomentose.

Postpronotal bristle long, black, inclinate. Dorsocentrals in

multiple rows, complete posteriorly. Acrostichals 2-serial,

complete posteriorly.

Legs with colour pattern: hind coxa in extreme base; mid

femur in apical 1/3, hind femur in apical 2/3 and tarsomere

5 of all legs brownish; fore tibia and fore tarsomere 1 with

brownish tinge; otherwise legs yellow. Hind trochanter

lacking spinules. Mid femur (Fig. 69, 70) slender, with 1 long

anterior subapical bristle, 1 long yellow basal bristle, 8 black

spinules in basal 1/3 and 2 posteroventral spinules in middle.

Hind femur (viewed laterally) constricted and bent near

middle, broader in apical half; with row of 8 fairly long

(scarcely longer than femur is deep) anteroventral bristles in

apical part, row of 5-6 dorsal bristles in basal part and 3-4

dorsal spinules just beyond midpoint of femur. Fore tibia

lacking prominent bristles. Mid tibia straight, rather slender,

with rows of ventral spinules and 1 longer subapical spinule.

Hind tibia (Fig. 71) with posterior apical comb greatly

modified, long, spur-like.

Wing (Fig. 72) 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 nearly

1.3 times longer than distance between apices of R1 and

R2+3. R4+5 and M divergent and slightly arcuate in apical

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.

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