Chen Ng(Pg61-69)

320

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

Province, Lachamunkorn, in secondary rain forest, sample n

°

 22003,

27 Mar.2002, coll. P. Grootaert (coll. RBINS).

Paratypes – Loei province, Na Haeo FIRS, Malaise trap: 1

male, 13-20 Mar.2000; 2 males, 15-21 Apr.2001; 2 males, 2

females, 29 Apr.2001; 1 male, 17-24 Jun.2001; 1 male, 24

Sep.-1 Oct.2001; 1 female, 2-4 Dec.2001; 2 males, 1 female,

Na Haeo, 4 Feb.2001, coll. Verapong Kiatsoonthorn & P.

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

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

monospinatus. Male: mid femur with black ventral spine just

beyond middle, abdomen with gland-like structures between

tergites 3-2 and 2-1, left cercus with 3 apical spines.

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

minute ocellars and long, cruciate inner verticals. Antenna

yellow. Postpedicel nearly 2.0 times longer than wide. Style

about 5 times longer than postpedicel. Palpus yellow.

Thorax dark brown. Scutum entirely tomentose. Postpronotal

bristle long, inclinate. Dorsocentrals in multiple rows,

complete posteriorly. Acrostichals 2-serial, complete

posteriorly.

Legs with colour pattern: hind femur brownish yellow in

apical 2/3, fore tarsomere 5 brown, mid and hind tarsomere

5 brownish yellow; otherwise legs yellow. Mid coxa with 2

brown bristles on outer side. Hind trochanter lacking spinules.

Mid femur (Fig. 5) with 3 yellowish long bristles in extreme

base, row of anteroventral brownish spinules before middle

and 1 short black spine just beyond middle. Hind femur

(viewed laterally) evenly thickened toward middle, with row

of 8 fairly long anteroventral bristles in apical part and some

prominent dorsal bristles in basal half. Fore tibia with 1 erect

bristle in apical part. Mid tibia with hardly prominent spinules

in apical part. Hind tibia unmodified.

Wing (Fig. 6) normally developed, covered with uniform

microtrichia; with pattern consisting of 2 brownish, large,

elongate oval spots separated more or less distinctly by pale

basal half of vein M; remainder parts finely infuscate, apex

almost hyaline. Vein R2+3 about 2.0 times longer than Rs.

Distance between apices of R2+3 and R4+5 subequal to

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

divergent and evenly arcuate in apical part. Halter with

contrast black elongate knob and pale stem.

Abdomen largely yellowish brown, bearing mostly scattered

dark setulae which are longer on pregenital segments, with

all tergites (except segment 8) of subequal in length, tergites

1-2 unmodified. Narrow gland-like structures present between

tergites 3-2 and 2-1.

Hypopygium (Fig. 7) brown. Hypandrium with 2 strong

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. 8)

divided; lower part broadened, with markedly developed

surstylar comb and 2 short apical spines, upper part elongate,

slender. Right surstylus (Fig. 10) large, subtriangular, divided

into 2 lobes in apical part, bearing numerous strong marginal

bristles; right lobe with 1 and left lobe with 2 spines,

respectively. Left cercus (Fig. 9) branched in apical part,

lacking long marginal bristles in basal part, with right lobe

bearing 3 long apical spines. Right cercus unbranched, short,

subrectangular, lacking spines, bearing several short marginal

bristles. Phallus short.

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

row of yellowish bristles. Abdomen lacking gland-like

structures. Terminalia shortened. Segment 8 normally

sclerotized. Proximal margin of sternite 8 without 2 anteriorly

directed rods. Apex of sternite 8 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 1.6-1.9 mm, wing length 1.4-

1.7 mm.

Etymology. – The name of this species refers to the 3 spines

on the male left cercus.

Phylogenetic relationships. – The relationships of S.

spinicercus are unclear beyond inclusion within the S.

graminum species group. The structure of the female

terminalia and the upper lobe of the left surstylus may suggest

closer relationships with the S. graminum (Fàllen) and its

allies, though the structure of the right surstylus resembles

that in S. nubilus Collin. S. spinicercus is the only species of

this group which has the gland-like structures on the male

abdomen.

Distribution and seasonal occurrence. – Thailand. Known

from two areas: Loei and Chantaburi provinces. Records are

almost from the whole year, except July, August, and most

part of September.

The S. seeluang species group

This is hitherto unknown group of Stilpon. Members of this

group are characterised by yellow thorax, tomentose scutum,

complete rows of acrostichal setulae, lack of gland-like

structures on male abdomen, small male terminalia with the

left cercus lacking apical spines, minute or absent bristles in

apical part of the left epandrial lamella, shortened female

terminalia. The entire group is presently known only from

the Oriental region and includes 6 species. S. leleupi Smith

described from South Africa (Smith, 1969) may also belong

to this group.

Stilpon crassinervis, new species

(Figs. 11-14)

Material examined. – Holotype - male, THAILAND: Phang-Nga

province, Khao Sok, sample n

°

 96035, 6 Apr.1996, coll. P. Grootaert

(coll. RBINS).

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