JHR 97: 241-254 (2024) yaa JOURNAL OF | 4Perreewed openscess our
doi: 10.3897/hr.97.1 19354 RESEARCH ARTICLE () Hymenoptera

The International Society of Hymenopterists RESEARCH

https://jhr.pensoft.net

A new species of the presocial potter wasp
genus Calligaster de Saussure, 1852 (Hymenoptera,
Vespidae, Eumeninae) from Vietnam

Cuong Quang Neuyen'’, Hoa Thi Dang!?, Lien Thi Phuong Neuyen'”?

I Lnstitute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18 Hoang Quoc
Viet Road, Nehia Do, Cau Giay, Hanoi, Vietnam 2 Graduate University of Science and Technology, Vietnam
Academy of Science and Technology, 18 Hoang Quoc Viet Road, Nehia Do, Cau Giay, Hanoi, Vietnam

Corresponding author: Lien Thi Phuong Nguyen (phuonglientit@gmail.com)

Academic editor: Michael Ohl | Received 23 January 2024 | Accepted 5 March 2024 | Published 28 March 2024
https://zoobank.org/AFO91 9BC-B9E 1-47 13-8656-2B657BCBE17D

Citation: Nguyen CQ, Dang HT, Nguyen LTP (2024) A new species of the presocial potter wasp genus Calligaster de
Saussure, 1852 (Hymenoptera, Vespidae, Eumeninae) from Vietnam. Journal of Hymenoptera Research 97: 241-254.
https://doi.org/10.3897/jhr.97.119354

Abstract

Taxonomic notes are presented on the genus Calligaster de Saussure (Vespidae: Eumeninae) from Vietnam.
A new species, Calligaster inflata sp. nov. is described and figured together with its nest. The male genitalia are
redescribed for C. himalayensis. A key is provided to all known species of the group in the Oriental Region.

Keywords

Calligaster, Eumeninae, key, new species, Oriental, Vietnam

Introduction

Potter wasps in the genus Calligaster have been considered to be one of several subsocial
or presocial lineages as species fully progressive provision their brood (Cowan 1991).
Their nests are made of many small pieces of leaves, as in the genus Zethus Fabricius,
and they nest together with sisters (Nugroho et al. 2016). Calligaster is a small genus,
with only six species distributed in the Oriental Region. Two of these species, C. cyano-
ptera de Saussure, 1855 and C. viridipennis Giordani Soika, 1960, are found in Indo-
nesia; two others, C. ilocana Selis, 2022 and C. williamsi Bequaert, 1940, are from the

Copyright Cuong Quang Nguyen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License
(CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

242 Cuong Quang Nguyen et al. / Journal of Hymenoptera Research 97: 241-254 (2024)

Philippines; while C. etchellsii (Cameron, 1909) is endemic to Malaysia and C. hima-
layensis (Cameron, 1904) is widely distributed from India through China to Laos and
Vietnam. The last species has hitherto been the only species recorded in Vietnam.

In the present work, based on specimens deposited in the Institute of Ecology and Bio-
logical Resources, Hanoi, Vietnam (IEBR), one species of the genus Calligaster is described
as new to science, together with its nest. In addition, the male genitalia of C. himalayensis
are redescribed in added detail, and a key is provided to all known species in the genus.

Materials and methods

The material examined in the present study is deposited in the collections of the In-
stitute of Ecology and Biological Resources (IEBR), Hanoi, Vietnam. Adult morpho-
logical and color characters were observed on pinned specimens with the aid of a
stereomicroscope. The male terminal sterna and genitalia were dissected out, cleared
in KOH, and mounted in hand-washing gel for observation and photography with a
stereomicroscope. Terminology follows Bohart and Stange (1965) and Carpenter and
Cumming (1985), while measurements follow Nguyen (2020); terminology for male
genitalia follows that of Kojima (1999) and Nguyen et al. (2023). Measurements of
body parts were made with an ocular micrometer attached to a stereomicroscope, with
accuracy to 0.1 mm. Nest characters were examined after the nest had been air-dried,
and the terminology of Williams (1919) was used for nest characters. Photographic
images of the wasps were obtained using a Nikon SMZ 800N Digital StereoMicro-
scope with ILCE-5000L/WAP2 digital camera attached, using Helicon Focus 7 soft-
ware for stacking; the plates were edited with Adobe Photoshop CS6.

Systematics

Genus Calligaster de Saussure

Calligaster de Saussure, 1852: 22. Type species: Calligaster cyanoptera de Saussure,
1852, by subsequent designation of Ashmead (1902: 205).

Note. A complete diagnosis of the genus has been recently provided by Nugroho et al.
(2016) and is therefore not repeated here.

Calligaster inflata CQ Nguyen, Dang & Nguyen, sp. nov.
https://zoobank.org/2B61 AAEB-9084-4DCE-B009-3367887 16F9D
Figs 1-10

Holotype (deposited in IEBR). Vietnam: 2; Vinh Phuc province, Ngoc Thanh, Me
Linh; 21°23'N, 105°42'E, 50 ma.s.L.; 18 April 2013; Nest-13-ML-Eu-03; D. T. Hoa leg.

Genus Calligaster from Vietnam 243

Diagnosis. This species can be distinguished from congeners by the following
combination of characters: Head in frontal view with inner compound eye margins
1.1 times further apart from each other at clypeus than at vertex. Clypeus in frontal
view wider than high, about 1.3 times as wide as high, apical margin produced and
round medially. Propodeum deeply excavated medially, with the excavation nearly
two-fifths of propodeal width and its margins marked laterally by ridges, dorsal surface
largely smooth, with some sparse strong punctures near concavity, posterior and lateral
surfaces bordered by blunt edge. First metasomal tergum with a median longitudinal
carina and next to this on each side consisting of a few rows of quite elongate punc-
tures, this part occupying one-third the width of the tergum, the other area on tergum
with strong and sparse punctures, interspaces between punctures smooth and usually
larger than their diameter; tergum II with small and sparse punctures, interspaces be-
tween punctures much larger than puncture diameter, about 3 to 4 times larger than
their diameter.

Description. Holotype. Female (Fig. 9). Body length (head + mesosoma + first
two metasomal segments) 20 mm; forewing length 17 mm.

Body black except two faint yellow spots on frons just above antennal toruli, dark
ferruginous marks near apical margin and at base of mandible, and dark brown propo-
deal valvula. Wings subhyaline, veins brown.

Body covered with dense, suberect, golden setae on head, mesosoma, and metaso-
mal segment I, and black setae on metasomal segments II-VI; setae longer on metano-
tum and dorsal surface of propodeum than on other body parts. Clypeus with coarse
punctures, punctures in middle tend to unite and form large longitudinal punctures,
with interspace strongly raised to form reticulations; frons with dense, deep, flat-
bottom punctures, interspaces between punctures narrower than their diameters and
raised to form reticulation; vertex less densely punctate, interspaces between punctures
usually narrower than their diameter and not raised to form reticulations; punctures
on gena dense, strong, well-defined, gena with a smooth band along occipital carina
running from near base to near vertex. Pronotum, mesoscutum, and metapleuron with
dense coarse punctures, punctures larger than punctures on frons; mesoscutum with
some smooth areas between punctures medially, with deep parapsidal furrows running
from apical margin to mid length, and two short and shallow longitudinal furrows lat-
erally; punctures on mesoscutellum similar to those near apical margin of mesoscutum;
metanotum with a shallow furrow medially, punctures smaller than those on mesoscu-
tum; margins of concavity of propodeum marked laterally by ridges, propodeum with
deep longitudinal fovea medially running from base to mid length of propodeum, with
a short longitudinal carina running from fovea to apical margin, rugosely striated area
occurring along two sides of fovea and carina; dorsal surface of propodeum largely
smooth, with some sparse strong punctures near concavity; lateral surface of propode-
um with strong, dense, well-defined punctures, interspaces between punctures smooth
but raised to from carina apically; apical margin above valvulae round. First metasomal
tergum with a median longitudinal carina bordered on each side by a few rows of
quite elongate punctures, this part occupying one-third width of tergum, other area
on tergum with strong sparse punctures, interspaces between punctures smooth and

244 Cuong Quang Nguyen et al. / Journal of Hymenoptera Research 97: 241-254 (2024)

usually larger than their diameter; tergum II with small sparse punctures, interspaces
between punctures much larger than puncture diameter, about 3 to 4 times larger than
their diameter; punctures on terga IN—V larger and denser than punctures on tergum
II; punctures on tergum VI sparse but larger than punctures on tergum II; punctures
on sternum IJ larger and denser than on tergum II; punctures on sterna III—V larger
and denser than on sternum II.

Head: \n frontal view 1.1 times as wide as high (Fig. 1), in dorsal view 1.7 times as
wide as long. Vertex well developed, strongly produced behind compound eye, without
cephalic fovea (Fig. 2). Distance from posterior ocelli to apical margin of vertex about
2.3 times distance from posterior ocelli to inner compound eye margin (Fig. 2). Occip-
ital carina incomplete, evanescent dorsally, weakly widened laterally, slightly produced
at one-third length from base (Fig. 5). Inner compound eye margins in frontal view
1.1 times further apart from each other at clypeus than at vertex (Fig. 1). Clypeus in
frontal view wider than high, about 1.3 times as wide as high, apical margin produced
and round medially (Fig. 1); in lateral view disc of clypeus gradually and weekly con-
vex from base to near apical margin, then depressed to apical margin. Mandible with
four prominent teeth. Antennal scape about 4.7 times as long as its maximum width;
flagellomere I about 1.5 times as long as its maximum width, flagellomere II as wide as
long, flagellomeres IU—IX wider than long, terminal flagellomere bullet-shaped, about
1.2 times as long as its basal width.

Mesosoma: About 1.1 times as wide as head and 1.1 times longer than wide in
dorsal view. Pronotal carina complete, raised into low lamella, angulate at lateral corner
before attaining dorsal part, reaching ventral corner of pronotum. Mesoscutum slightly
convex, shorter than wide, 0.9 times as long as wide between tegulae (Fig. 3). Disc of
mesoscutellum rectangular, nearly flat, with lateral margin truncate. Disc of metano-
tum weakly produced posteromedially. In lateral view, mesoscutellum at same level as
mesoscutum (Fig. 5). Propodeum deeply excavated medially (Fig. 4), with excavation
nearly two-fifths of propodeal width and its margins marked laterally by ridges, poste-
rior and lateral surfaces bordered by blunt edge.

Metasoma: Metasomal tergum I in dorsal view strongly widened after short, basal,
parallel-sided part to one-third basally, then gradually narrowly to apical margin (Fig. 6),
1.4 times as long as wide, in lateral view strongly convex from base to apical margin.
Metasomal segment II petiolate at base (Figs 7, 8), tergum II in dorsal view wider than
long, 1.05 times as wide as long (Fig. 8), and shorter than tergum J; sternum I in lateral
view straight from base to about one-half length, then straight to apical margin (Fig. 7),
and slightly produced medially. Terga I-VI not raised and without lamellae (Figs 7, 8).

Nest. (Fig. 10). One nest of this species was collected at Me Linh Station for Biodi-
versity of the Institute of Ecology and Biological Resources (IEBR), Vinh Phuc Province
on 23 March 2013. The nest consists of four cells, each bent at the neck and enlarged
at the bottom. ‘The inner diameter of the open end of cells varied from 5 to 6 mm. ‘The
oldest cell was strongly secured to a twig of a tree, and from its underside the second cell
and then those following depend. The length of cells measured 35 to 36 mm. There was a
well-defined roof covering the entrance of the cells (Fig. 10). The entrance of the cell was
closed up with leaf-bits. Those plugs were concave and smooth surfaced on the outer side,

Genus Calligaster from Vietnam 245

Figures |-6. Calligaster inflata sp. nov. | head, frontal view 2 head, dorsal view 3 mesosoma, dorsal
view 4 propodeum, dorsal view 5 head and mesosoma, lateral view 6 metasomal tergum I, dorsal view.
Scale bars: 1 mm.

rather crude on the inner surface. Three of them had a small hole on the wall of the cell
and the remaining cell was intact. Three cells with a small hole on the wall were opened
for examination of structural details. Unfortunately, they were empty except for their

246 Cuong Quang Nguyen et al. / Journal of Hymenoptera Research 97: 241-254 (2024)

cocoons. The cocoon was 20 to 21 mm long. They were thickest in the part facing the
open end of the cells and thinner at the wall of the cells. The feces and the prey remain
were always at the bottom of the cells and positioned outside the cocoon. The intact cell
was preserved and a female wasp emerged from it on 18 April 2013.

9

Figures 7-9. Calligaster inflata sp. nov. 7 metasoma, lateral view 8 metasomal terga I-VI, dorsal view

9 habitus, laterodorsal view. Scale bars: 1 mm.

Genus Calligaster from Vietnam 247

Figure 10. Cad/igaster inflata sp. nov. nest. Scale bar: 1 cm.

Distribution. Vietnam (northern part).

Etymology. ‘The specific epithet is from the Latin inflatus (meaning swollen), and
refers to the swollen metasomal segment I in this species.

Remarks. The new species is similar to C. himalayensis in that both have the cl-
ypeus, frons, and mesoscutum with coarse dense punctures, with interspaces between
the punctures smaller than a puncture diameter and raised to form reticulation; and
the lateral part of metasomal tergum I with strong sparse punctures. However, it differs
from C. himalayensis in having metasomal tergum I about 1.4x as long as wide, with
a median longitudinal carina and next to this on each side consisting of a few rows of
noticeably elongate punctures, this part occupying one-third the width of the tergum
(metasomal tergum I about 1.8x as long as wide, with a median longitudinal carina
and next to this on each side consisting of a few longitudinal striae, this part occupying
about half the width of the tergum in C. himalayensis); and body punctures larger and
coarser than in C. himalayensis.

Calligaster himalayensis (Cameron, 1904)
Figs 11-21

Zethus himalayensis Cameron, 1904: 13, 2, “Sikkim” (The Natural History Museum,
London).

Calligaster himalayensis; Bequaert 1928: 157 (holotype examined; possibly a valid
species).

Zethus hymalayensis |]; Giordani Soika 1941: 216 (incorrect spelling of Zethus hima-
layensis Cameron; syn. of C. cyanoptera de Saussure).

248 Cuong Quang Nguyen et al. / Journal of Hymenoptera Research 97: 241-254 (2024)

Note. This species was recorded from Vietnam by Nguyen et al. (2014) and Nugroho
et al. (2016). The species occurs in the northern and central parts, as well as the Tay
Nguyen highlands. Refer to Nugroho et al. (2016) for the diagnosis of this species.

Material examined. VIETNAM: 14, Cao Bang, Nguyen Binh, Thanh Cong,
22°32.5'N, 105°53'E, alt. 1000 m, 8 Aug. 2012, Lien Thi Phuong Nguyen et al. leg.;
12, Cao Bang, Tra Linh, Ho Thang Hen, 22°45'47.5"N, 106°53'35.7"E, alt. 619 m,
20 May 2023, Lien Thi Phuong Nguyen, Ngat Thi Tran, Cuong Quang Nguyen leg.;
19, 14, Tuyen Quang, Ham Yen, Phu Luu, Cham Chu NP, alt. 200 m, Jun. 2011,
Lien Thi Phuong Nguyen leg.; 19, Son La, Moc Chau, Chieng Son, Chieng Ve, 21
Jun. 2015, Long Dang Khuat leg.; 12, Dien Bien, Dien Bien, Pa Thom, 20°17'50"N,
102°54'37"E, alt. 693 m, 01 Mar. 2023, Hoa Thi Dang leg.; 19, 14, Dien Bien, Tua
Chua, Muong Fang, 21°50'46"N, 103°22'53"E, alt. 735 m, 04 Mar. 2023, Hoa Thi
Dang leg,; 14, Vinh Phuc, Me Linh, Me Linh Station, 25 May 2013, Nest#ML-2013-
Eum 1, Lien Thi Phuong Nguyen leg.; 19, Vinh Phuc, Me Linh, Me Linh Station, 2
Jun. 2018, Cuong Quang Nguyen leg.; 19, 14, Vinh Phuc, Me Linh, Me Linh Sta-
tion, 01 Jul. 2020, Hoa Thi Dang leg.; 14, Hoa Binh, Ngo Luong, Ngoc Son NR,
20°25'13.3"N, 105°18'36"E, alt. 200 m, 27 Aug.2020, Ngat Thi Tran leg.; 14, Thanh
Hoa, Ba Thuoc, Thanh Son, alt. 200 m, 16-18 Jun. 2003, Huong Thi Thu Nguyen leg.;
19, Thanh Hoa, Thuong Xuan, Van Xuan, Hon Can, Xuan Lien NP, 19°52'27.5"N,
105°14'20.8"E, alt. 106 m, 24 Aug. 2012, Lien Thi Phuong Nguyen leg.; 14, Thanh
Hoa, Quan Hoa, Pu Hu NP, 20°29'13.3"N, 104°57'47.2"E, alt. 408 m, 13 Jun. 2016,
Lam Xuan Truong, Dac Dai Nguyen, Ngat Thi Tran, Linh Ngoc Ha leg.; 19, Ha Tinh,
Vu Quang NP, 18°17'45"N, 105°22'29"E, alt. 78 m, 12 Jun. 2023, Cuong Quang
Nguyen, Lien Thi Phuong Nguyen, Neat Thi Tran leg.; 19, Quang Nam, Song Thanh,
Cha Vai, alt. 400-600 m, 29 Apr. 2005, collectors from the Insect Systematic Depart-
ment (IEBR) leg.; 19, Kom Tum, Dak Ha, Dak Mar, Dak Uy SUF, 14°33'04.6"N,
107°55'08.0"E, 19 Jun. 2012, alt. 630 m, Lien Thi Phuong Neuyen leg.; 34, Gia
Lai, Chu Se, 14 Apr. 2013, Lien Thi Phuong Nguyen leg.; 19, Gia Lai, KBang, Kon
Chu Rang NR, 14°31'10.4"N, 108°36'24.9"E, 6 Sep. 2018, Lam Xuan Truong, Tuan
Viet Luong leg.; 12, Dak Lak, Buon Me Thuot city, Tan Hoa, 28 Jul. 2020], QH-L22-
01, Bui Thi Quynh Hoa leg., 292, Dak Nong, Dak Giong, Dak Som, Ta Dung NP,
11°50'16.1"N, 107°59'16.7"E, alt. 475 m, 6 May 2016, Nest#VN-TN-2016-E-01,
Lien Thi Phuong Nguyen, Dai Dac Nguyen, Ngat Thi Tran leg.

The male genitalia of this species were described by Giordani Soika (1960) but are
redescribed here with added detail.

Description. Male genitalia. As in Figs 16-19. Parameral spine with setae (Fig.

16). Volsella flattened, wide on inner aspect, without setae at top (Fig. 16). Digitus
gradually narrow from base to apex, with round apex, with setae on apical half (Fig.
17). Penis valve (Fig. 18), about 1.9 times as long as basal apodeme, in profile apical
part strongly produced into a large pointed lobe (Fig. 19), with apical part smooth
(Fig. 19), middle rod slightly shorter than basal apodeme (Figs 18, 19).

Nest. Three nests comprising 15 cells of this species were collected at Me Linh Sta-
tion for Biodiversity of the Institute of Ecology and Biological Resources (IEBR), Vinh

Genus Calligaster from Vietnam 249

Figures 11-15. Calligaster himalayensis \|, 13-15 female 12 male II head, frontal view 12 head,

frontal view 13 mesoscutellum, metanotum, and propodeum, dorsal view 14 metasomal tergum I, dorsal

view 15 metasomal terga II-VI, dorsal view. Scale bars: 1 mm.

Phuc Province on 1* July 2020. These nests were made on the branch of bougainvillea.
They were not only protected by the roof like the nest of C. inflata, but the entire nests
were covered with leaves (Fig. 21). The detailed structure of these nests was similar nest
of C. inflata: the nests consisted of four to six cells, each bent at the neck and enlarged at
the bottom; the inner diameter of open end of cells varied from 6 to 6.5 mm; the oldest
cell was strongly secured to a twig of a tree, and from its underside the second cell and
then those following depend; the entrance of the cell was closed up with leaf-bits; those
plugs were concave and smooth surfaced on the outer side, rather crude on the inner
surface. The length of the cells measured 32 to 40 mm. Among 15 cells in three nests
examined, three individuals developed to the mature stage (two females and one male),
other 12 cells died. Of 12 dead cells, three died at the larval stage for unknown reasons;
six cells with a small hole in the wall and they were empty except for their cocoons;

250 Cuong Quang Nguyen et al. / Journal of Hymenoptera Research 97: 241-254 (2024)

Figures |6-21. Calligaster himalayensis. 16-19 male genitalia 16 inner aspect of paramere with volsella
and digitus I7 volsella and digitus 18 aedeagus, ventral view 19 aedeagus, lateral view 20-21 adult and

nest. Scale bars: 1 mm.

the other three cells containing prepupae were attacked by an eulophid species. The
cocoon was 20 to 22 mm long. They were thickest in the part facing the open end of
cells and thinner at the wall of the cells. The feces and the prey remain were always at
the bottom of the cells and positioned outside the cocoon.

Distribution. India: Sikkim; China: Guangdong, Hong Kong; Laos; Vietnam.

Key to species of the genus Calligaster in the Oriental Region

This key is based on those by Nugroho et al (2016) and Selis and Femia (2022) (un-
less the sexes are specified, the character states given in the key can be applied to both
sexes). [he characters of C. cyanoptera, C. etchellsii, C. viridipennis, C. williamsi, and
C. ilocana were taken from Bequaert (1928), Giordani Soika (1960), Nugroho et al.
(2016), and Selis and Femia (2022). Calligaster himalayensis and C. inflata sp. nov.
were examined based on specimens from Vietnam.

Genus Calligaster from Vietnam 251

Clypeus and frons with dense coarse punctures, interspaces between punc-
tures raised to form reticulation (Figs 1, 11). Mesoscutum with dense, strong
or coarse punctures, interspaces between punctures smaller than puncture
diameter and slightly or strongly raised to form reticulations (Fig. 3).......... Pe
Clypeus and frons with strong punctures, interspaces between punctures
smooth (figs 3-6 in Selis and Femia 2022). Mesoscutum with sparser and
less-strong punctures, interspaces between punctures about 2—5 times punc-
tureidiametcm(1168’7,,.8 ir Sclis arid Pema 2022). Vt. sensastissnnavadassecharaalacatatts 4
Metasomal tergum I less than 1.5 times as long as wide, with a median lon-
gitudinal carina and next to this on each side consisting of a few rows of
noticeably elongate punctures, this part occupying one-third width of tergum
(BEG) eli Awasticsve Ry coadabaietnesy Somalitse seh piiuwas sae abads Bavdaleanedl C. inflata sp. nov.
Metasomal tergum I about or greater than 1.8 times as long as wide, with a
median longitudinal carina and next to this on each side consisting of a few
longitudinal striae, this part occupying about half width of tergum (Fig. 14;
figs.7-,-9:in Nero hover ab 2G )s weeseartosiusucetcublcedcswel icudvccensvencceniengeetencees 3
Metasomal segment I in dorsal view relatively slender, about 2.5 times as long
as its maximum width (fig. 7 in Nugroho et al. 2016); tergum I hardly punc-
tured, so that dorsal striae are more or less conspicuous. In male, proximal
margin of penis valves in ventral view lobed at upper lateral margin (fig. 5 in
Giordani Soika 1960), and in profile apical part strongly produced to a trian-
eulalobe tic xOritt Giordani SOikas* LG), 4 cose. Sabc sev vcue et soncTevesaeertescesteee tenia
Ssh I RINE |e SO UMNrCL + Set NERRONUh oh Nn POPP INE. C. cyanoptera de Saussure, 1852
Metasomal segment I in dorsal view shorter and stouter, about 1.8 times as
long as its maximum width (fig. 9 in Nugroho et al. 2016); tergum I with
dense distinct punctures, so that dorsal striae inconspicuous. In male, proxi-
mal margin of penis valves in ventral view without lobe at upper lateral mar-
gin (fig. 1 in Giordani Soika 1960), and in profile apical part strongly pro-
duced in to a sharply pointed lobe (Fig. 19; fig. 2 in Giordani Soika 1960) ..
JR TT) Soren feCe ay. ere er Pane ev C. himalayensis (Cameron, 1904)
Male clypeus in frontal view about 2 times as wide as high; apical margin with
a deep semi-elliptic emargination............... C. etchellsii (Cameron, 1909)
Male clypeus in frontal view equal or less than 1.5 times as wide as high; api-
eal mmarein witha shallower-emareination sist. src nsitedsbnnraesttucnensnaeeeteneeeceates 5
Metasomal tergum I in lateral view strongly convex dorsally and in dorsal
view strongly convex along lateral margins, with faint oblique striae. In male,
proximal margin of penis valves in profile apical part weakly produced (fig. 8
in Giordani Soitka 19GO)* 2.4.8 2540-4. C. viridipennis Giordani Soika, 1960
Metasomal tergum I in lateral view flat dorsally and in dorsal view almost
parallel along lateral margins, with a sharp longitudinal carina in the middle,
flanked by a series of posteriorly diverging carinae. In male, proximal margin
of penis valves in profile apical part strongly produced (figs 9, 10 in Selis and
Herta 22 ee ber hs ee eee ae re LoS A NO eee Le 6

252 Cuong Quang Nguyen et al. / Journal of Hymenoptera Research 97: 241-254 (2024)

6 Mesoscutum with parapsidal furrows shallow, with few punctures. Anterior
margin of mesoscutellum with a shallow and irregular transverse furrow; mes-
oscutellum dull with fine punctures (fig. 8 in Selis and Femia 2022). Female
clypeus more sparsely punctured on disc (fig. 6 in Selis and Femia 2022).
Male clypeus regularly convex, apical emargination semicircular and as wide
as deep (fig. 5 in Selis and Femia 2022). Head entirely black in both sexes ...
Petes StS ain Oe aR, ire reel, Len. Mun Eee C. williamsi Bequaert, 1940

- Mesoscutum with parapsidal furrows well-defined and deep, densely punc-
tured. Anterior margin of mesoscutellum crenate, forming six deep pits; mes-
oscutellum weakly shiny with big deep punctures and micropunctate inter-
spaces (fig. 7 in in Selis and Femia 2022). Female clypeus more densely punc-
tured on disc (fig. 4 in Selis and Femia 2022). Male clypeus with a median
transverse depression, apical emargination wider than deep (fig. 3 in Selis and
Femia 2022). Male with yellow lines on mandible and scape and rounded
yellow spots above antennal insertions ...............eese C. ilocana Selis, 2022

Discussion

Calligaster etchellsii (Cameron, 1909) was first described under the genus Zeuthus and
was based on a single male from “Kuching, Borneo”. In the description of this species,
Cameron mentioned that the, “clypeus almost as wide as long” (Cameron, 1909: 206).
Bequaert (1928: 157) examined the holotype of this species and moved it to the genus
Calligaster. He noted that, “This is quite a distinct species in the shape of the clypeus,
which is unusually wide (twice as broad as high) and ends in a deep semi-elliptic
emargination”. Nugroho et al. (2016) used the character of the clypeus as described
by Bequaert (1928) (clypeus twice as broad as high) to separate the species from three
other species. Neither Cameron (1909) nor Bequaert (1928) indicated how to measure
the width of the clypeus in their studies so we could not know which measurement was
correct. We visited the website of the NHML where the holotype of C. etchellsii was
deposited, but no information on this species was found. In the study of Nugroho et
al. (2016) and Selis and Femia (2022), the males of species of Calligaster usually have
the clypeus much wider than high, about 1.4 to 1.5 times wider than high (though the
proper method for measuring the height and width of the clypeus was not mentioned
in their study). In our study, the width of the males of species of Calligaster (C. hima-
layensis and C. inflata sp. nov.) have the clypeus about 1.3 to 1.4 times wider than
high (height of clypeus in frontal view is measured as a distance from the bottom of
the dorsal emargination to the apex (medially), and width of the clypeus is measured
between the extreme corners of the clypeus, at the widest point), and never “as wide as
long” as mentioned by Cameron (1909). Accordingly, for the moment we tentatively
use in the above key the character as mentioned in Bequaert (1928). Further extensive
field sampling will be needed to obtain more specimens and study the taxonomy of
this species carefully.

Genus Calligaster from Vietnam 253

Acknowledgements

We are very grateful to Michael S. Engel for revising some of the English for the manu-
script. We thank subject editor and both reviewers for their valuable comments on the

manuscript. The present study was supported by a grant from the Vietnam Academy
of Science and Technology (VAST04.07/23-24).

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