Anthidiellum is a small-robust genus that has an arcuate subantennal suture (Fig. 2C), carinated omaulus (see Fig. 2A), open scutoscutellar suture (see Fig. 2B), and presence of a propodeal fovea behind the spiracle. Two distinct subgenera were recognized in Thailand: Pycnanthidium Krombein, 1951, with a generally black-yellow integument and a prominent frontal carina on T1; and Ranthidiellum Pasteels, 1969, which is slightly larger in comparison, with a general black to reddish brown integument (Fig. 4A, B), and with a general appearance similar to a stingless bee.

11 (3♀, 8♂). Myanmar (new record): 1♀, Dawei city, Dawei Hospital (13°59.117'N, 98°7.479'E, alt. 4 m), 3 May 2018, N. Warrit et al. (CUNHM: BSRU-AA-6909); Thailand: 4♂, Chumpon, Lang Suan District, Ban Suan Phueng, (10°01'N, 99°03'E, alt. 10 m), 15 Jul. 2003, N. Warrit (CUNHM: BSRU-AA-1245–1248); 1♀, Khon Kaen (new record), Phu Wiang District, 26 May 2016, N. Warrit et al. (CUNHM: BSRU-AA-4482); 1♂, Surat Thani, Koh Samui District, 17 Jul 2003, N. Warrit (CUNHM: BSRU-AA-1244); 1♀, 3♂, Ubon Ratchthani (new record), Phu Chong Na Yoi National Park, Trail to National Park Protection unit PorJor5 (14°33'4.35"N, 105°25'36.80"E, alt. 216 m), on Colona auriculata (Desf.) Craib. [Malvaceae], 28 Sep. 2020, N. Warrit et al. (CUNHM: BSRU-AB-1367–1370).

Indonesia (Bangka, East Kalimantan, Java, Sumba, Maluku Island), LAOS (Houaphanh), Malaysia (Negiri Sembilan, Penang), Myanmar (Dawei, new record), Philippines (Palawan), Singapore, Thailand (Chaiyaphum, Chiang Mai: Tadauchi and Tasen 2009, Chonburi, Chumpon, Khon Kaen, Nan, Surat Thani, Ubon Ratchathani (new record), Yala).

This species can be rarely found in the Southeast Asian region. A similar species, Anthidiellum (Pycnanthidium) carinatum (Wu, 1962), is known from China (Hainan, Yunnan) and India (Tripura) (see Niu et al. 2016; Sardar et al. 2022).

Within subgenus Pycnanthidium, this species has a small black body (3.9–5.0 mm) with yellow maculations on all tagmata. It differs from other congeners by its metasomal coloration, i.e., T1 with yellow markings laterally, T2 entirely black, T3–T6 with broad yellow bands, mostly interrupted medially on T3; axilla yellow; broad yellow marginal band on scutellum, medially interrupted; outer surface of the hind tibia and hind basitarsus with longitudinal carinae; black apical comb of S5 in male interrupted medially resembles small notch; gonostylus bifid. However, this species is similar to A. carinatum (Wu, 1962) from China, although Niu et al. (2016) suggested subtle differences, primarily related to punctures size and color pattern.

Bidens pilosa L. (Asteraceae), Muntingia calabura L. (Muntingiaceae) (Soh et al. 2016); Microcos tomentosa Sm. (Malvaceae) (Pasteels 1972); an individual from Ubon Ratchathani was found collecting pollen on the flower of Colona auriculata (Desf.) Craib. (Malvaceae).

Anthidiellum smithii was originally reported in Thailand from Yala province as A. minutissimum Bingham, 1903. More than a hundred years later, Tadauchi and Tasen (2009) reported it from Chaiyaphum and Chiang Mai provinces. Variations in color pattern of A. smithii are widely recognized, as noted by Pasteels (1972) and Soh et al. (2016).

In this study, four males collected at the same time and place in Chumpon Province display varying color patterns. Yellow teardrop markings on the frons are small in two specimens (Fig. 1E, F) (BSRU-AA-1246, BSRU-AA-1247 though the antero-lateral scutal bands are different in size), whereas teardrop marking is expanded in specimens BSRU-AA-1248, and absent in BSRU-AA-1245. All specimens examined have yellow supraclypeal area that is medially interrupted; however, a female from Khon Kaen (BSRU-AA-4482) (Fig. 1D) and one male from Ubon Ratchathani (BSRU-AB-1370) have a yellow marking on its basal area while others do not. Color variation in this species thus can occur in sympatric populations and may be a continuous trait. More discussion on yellow maculation variations is elaborated by Soh et al. (2016).

Figure 1. 

Anthidiellum smithii (Ritsema, 1874) A, B lateral habitus of females from Myanmar (BSRU-AA-6909) and Khon Kaen (BSRU-AA-4482), Thailand, respectively C–F faces of Myanmar female, Khon Kaen female, and Chumporn males (BSRU-AA-1245, 1247). Scale bars: 1 mm (A, B); 0.5 mm (C–F).

3 (3♀). Myanmar: 1♀ holotype, Rangoon [= Yangon, Myanmar], 1–87 Bingham coll., Anthidium latipes ♀ Bingh Type B.M. TYPE HYM. 17a.1873, Col. C.T. Bingham. 96–30. (NHMUK 014026066); Thailand: 2♀, Phang Nga, Kapong District, Tha Na Subdistrict (8°41'38.14"N, 98°24'28.87"E, alt. 29.4 m), 30 Apr. 2020, A. Kaosung (CUNHM, BSRU-AB-0162, 0163).

(2023). Myanmar: Yangon, Yangon District, (16°47'12.3"N, 96°08'38.1"E) observed by ‘chimik’ on 25 Apr. 2022. (observation id: 113229246). Thailand: Chiang Mai, Mueang District, Suthep-Pui (18°49'00.5"N, 98°55'26.8"E, accuracy 240 m) observed by ‘jackychiangmai’ on 9 Apr. 2023 (observation id: 154207614), and on 13 Apr. 2023 (observation id: 154700134 and 154702585).

China (Yunnan), Myanmar (Yangon), Thailand (Chiang Mai (new record from iNaturalist 2023), Phang Nga (new record)).

Anthidiellum latipes can be assigned to a group of Asian Pycnanthidium which includes A. butarsis Griswold, 2001, A. ramakrishnae (Cockerell, 1919), A. rasorium (Smith, 1875), A. coronum (Wu, 2004), and A. cornu Tran & Engel, 2023. The group contains medium-sized bees without carina on their hindlegs (Griswold 2001; Niu et al. 2016; see also Tran et al. 2023).

Marigold (Tagetes erecta L., Asteraceae, see Fig. 2E) and also yardlong bean (Vigna unguiculate (L.), Fabaceae).

Figure 2. 

Female of Anthidiellum latipes (Bingham, 1897) from Phang Nga, Thailand (BSRU-AB-0162) (A–E), and the female holotype of A. latipes from Yangon, Myanmar (NHMUK 014026066: picture modified from NHMUK data portal) (F) A lateral habitus B dorsal habitus C face D lateral angle showing the omaulus and hind legs E female wandering on the marigold flower (Tagetes erecta L.), photographed by Andaman Kaosung F lateral habitus. Scale bars: 2 mm (A, B, D); 1 mm (C, F).

The knowledge on the Asian Pycnanthidium is relatively scant due to the limited material and the damages in type specimens such as in Anthidiellum ramakrishnae (Griswold, 2001), and with the materials of A. coronum (discussed below). The female holotype of A. latipes from Myanmar is also not in good condition, the head and most of the legs were missing while the mesosoma and metasoma were glued together.

There is a possibility that A. coronum (Wu, 2004) is a junior synonym of A. latipes, as the color patterns on the supraclypeal area (Fig. 2C), hindlegs (Fig. 2D), and the shape of enlarged hind basitarsus, with ~ 1.3 length/width ratio, are more or less similar. In addition, the Thai specimens and a specimen recorded from Myanmar (through iNaturalist) share similar maculation on the supraclypeal area as seen in A. coronum, including the presence of mesad process running along the upper rim of the antennal socket.

1♀. Khao Ram, Siam [= Thailand: Nakhon Si Thammarat: Ronpibun, Khao Ramrome], 750–1200 [possibly altitude], 24 Feb. 1922, Anthidium apicepilosum Dover, 1926 (holotype NHMUK: 014026685).

Malaysia (Negeri Sembilan, Penang, Selangor), Thailand (Nakhon Si Thammarat). The species is rarely found, hence the records are based on the original designation (Dover 1929) and the additional report of their nest (Pagden 1934)

Anthidiellum apicepilosum has a black body with distinct brownish coloration disrupted. Since only the female is known, the most comparable characters include the following: clypeus, scape, lower paraocular area, tegula, axilla, and the margin of scutellum brownish; scutum black; wing base conspicuously dark brown, clearly contrasting to apical hyaline parts on 1^st submarginal cells; T1–T5 with reddish to brownish ferruginous apical band that becomes wider on the rear segments; T6 black; the rear of the metasoma covered with yellowish hairs; foreleg light brownish, generally brighter than in midleg and hindleg, which are almost black on their tibia and basitarsus. According to Pagden (1934) and Pasteels (1972), the male is superficially similar to the female but has lighter ferruginous leg parts especially on midleg and hindleg; S5 with a marginal black comb (> 60 teeth), gonoforceps bifid as in other Ranthidiellum species.

This is the first species of Ranthidiellum that has been documented for its nesting biology (Pagden 1934). In morphology, the species is very close to Anthidiellum rufomaculatum (Cameron, 1902) with a minor difference in that the female holotype of “Protoanthidium rufomaculatum” [= Anthidiellum rufomaculatum, female from Kuching, Sarawak, Malaysia] has more minute paraocular marks, more slender marginal bands on its axilla and scutellum, and a reddish black translucent band present basally on the black integument of T1–T5. However, to confirm the status, there is no certain evidence that the males described by Pagden (1934) are the exact Anthidiellum apicepilosum, even though the locality of Bakit Kutu, Selangor, is adjacent to the Negeri Sembilan, where the female paratype was caught (further discussion in Nalinrachatakan et al. 2021b).

Figure 3. 

Female holotype of Anthidiellum apicepilosum (Dover, 1929) (NHMUK: 014026685) A lateral habitus B face C rear view of metasoma showing T6 D dorsal view and labels, modified from NHMUK data portal. Scale bars: 2 mm (A); 1 mm (B, C).

(6♀, 1♂). Same specimens as in Nalinrachatakan et al. (2021b).

(2023). Thailand: Chiang Mai, Mueang District, Suthep Subdistrict (18°49'0.47"N, 98°55'26.81"E) uploaded by ‘jackychiangmai’ on 27 Oct. 2022 (observation id: 140223648).

Thailand (Chiang Mai, Nakhon Ratchasima, Phayao). The species is rare and appears to be endemic.

Plant family Amaranthaceae (possibly Achyranthes aspera L., commonly known as devil’s horsewhip), shown in the iNaturalist observation noted above. Also, the bee must mobilize plant resin as do other Ranthidiellum species (Pagden 1932; Pasteels 1972; Nalinrachatakan et al. 2021b).

Anthidiellum ignotum has distinct sexual dimorphism in which the male particularly had its base coloration brighter, with a noticeable black facial mark. More details on the presence of Ranthidiellum species in Thailand and its variation were discussed in Nalinrachatakan et al. (2021b).

Figure 4. 

Comparing specimens of Anthidiellum (Ranthidiellum) recently collected from Thailand, and its cleptoparasite A female Anthidiellum ignotum Engel, 2009 (BSRU-AA-1249) B female paratype of Anthidiellum phuchongense Nalinrachatakan & Warrit, 2021 (BSRU-AB-0159) C male paratype of cleptoparasite Stelis flavofuscinular Nalinrachatakan & Warrit, 2021 (BSRU-AB-0156). Scale bar: 2 mm.

(5♀, 1♂). Same specimens as in Nalinrachatakan et al. (2021b). Holotype was transferred to NHMUK in April 2023..

Thailand (Ubon Ratchathani). From a survey in other adjacent national parks in Ubon Ratchathani, there is evidence that Ranthidiellum is present through an abandoned nest with collapsed structures (i.e., resin became opaque, whitish, and the entrance apically fractured).

Mobilizing the resin of plants in the family Dipterocarpaceae, possibly Dipterocarpus obtusifolius Teijsm. ex Miq., which is broadly distributed along their nesting habitats.

Stelis flavofuscinular Nalinrachatakan & Warrit, 2021.

The species-group name phuchongensis is changed to phuchongense following a mandatory change for gender agreement under ICZN article 34.2. The species was discovered to build its nest in a dipterocarp forest in Phu Chong Na Yoy National Park, in a preexisting hole near water stream. Their nesting structures are unique, with a distinct downwardly curved, resinous, translucent tube. Further details of its nesting biology and morphology variations were discussed in Nalinrachatakan et al. (2021b).

Bathanthidium is an Asiatic genus consisting of small to medium-sized species that are mostly found in China. They come with almost black body and distinct yellow maculation (see Fig. 5); face without juxta-antennal carina (Fig. 5E), preoccipital ridge and omaulus not carinate; if omaular carina present, then it does not continue to the venter; presence of propodeal fovea behind propodeal spiracle. The genus was revised by Niu et al. (2019).

Figure 5. 

Type specimen of Stelis siamensis Friese, 1904, male, from Nan province, Thailand, which was recently synonymized with Bathanthidium (Manthidium) binghami (Friese, 1901) A lateral view B dorsal view C posterior angle of metasoma D original label E face F dorsal of metasoma. Scale bars: 1 mm.

(2♂). India: 1♂, West Bengal, Buxa Tiger Reserve, 22 miles, East Damanpur (26°37.067'N, 89°33.633'E), 27 Mar. 2019, A. Rameshkumar (ZSI) as in Sadar et al. (2022). Thailand: 1♂, Siam [= Thailand], Hinlap [= Nan province, “Hinlap” must refer to the area of “Baan Hinlap”, or “Huai Hinlap reservoir” as currently named (not in Chaiyaphum province) in Pua district, Sila lang Subdistrict], Januar [= January], H. Fruhstorfer, Stelis siamensis, ♂, 1904, Friese det., Type (ZMB).

(2023). Thailand: Chiang Mai Province, Chiang Dao District, (19°24'44.3"N, 98°55'17.3"E) observed by ‘charlieglasser’ on 23 Mar 2023 (observation id: 160344574 and 160340826).

China (Yunnan), India (Sikkim, West Bengal), Myanmar (Tenasserim), Thailand (Chiang Mai (new record from iNaturalist 2023), Nan), Laos (Luang Prabang).

Bathanthidium binghami has a robust, small to medium-sized body with black integument disrupted by striking yellow markings. The species is distinctly separated from its congeners by the combination of the follows: yellow on its mandible, clypeus, and paraocular area that do not exceed beyond the antennal socket plane; narrow yellow stripe laterally on T2–T5, while tending to abut together on the rear segment; yellow stripe on T6 and also T7 in male; rounded omaulus; T6 (also in the smaller male T7) sub-truncate, with distinct median elevation that extends its apical margin (Fig. 5C, F; Niu et al. 2019: fig. 8E).

Bathanthidium was revised by Niu et al. (2019), where Stelis siamensis Friese, 1925, historically collected from Nan, Thailand, was synonymized under B. binghami. Niu et al. (2019) also thoroughly provided pictures of the female holotype of “Paraanthidium concavum” in comparison to other species. Sadar et al. (2022) pointed out the problematic documentation of its distribution (erroneously recorded for India) while confirming that B. binghami was found in India. The species displays the unique sub-truncate apical terga in both sexes.

Through personal communication with Mr. Charles H. Glasser, who provided the iNaturalist records, we know that the bee inhabits farmland cultivated by the indigenous people of Lisu tribe.

An old-world genus which is mostly discernable from other genera by its more slender, striking black-yellow body, with a distinct juxta-antennal carina (Fig. 6B), rounded preoccipital ridge, carinated omaulus (see Fig. 6A, C), and rounded scutellum (Fig. 6B). Male sterna lack apical comb, penis valve enlarged, and pointed apically. The genus comprises four subgenera with 21 species in the Afrotropical, Palaearctic and Indo-Malayan regions (Kasparek and Griswold 2021). This work focuses on the subgenus Hemidiellum which has only one species to date. The bee subgenus Hemidiellum has a relatively small body length (~ 6–7 mm; Fig. 6) compared to its congeners, with the combination of characters as follow: omaular carina complete; distinct juxta-antennal carina; subantennal suture almost straight; upper margin of keirotrichiate area of hind tibia curved, not carinated; T4–T6 laterally with small tubercles in both sexes; arolia present. In addition to the type species, Gupta (1993) previously assigned Eo. punjabense Gupta & Sharma, 1993 to the subgenus Hemidiellum (see also Kasparek and Griswold 2021).

Figure 6. 

Eoanthidium (Hemidiellum) riparium (Cockerell, 1929). Female holotype of Dianthidium riparium Cockerell, 1929 (syn.) from Thailand (A, B). Male from Thailand (BSRU-AB-4360) (C, D). Female from Laos (BMNH-ENT-2017-196 (ACQ)) (E), Female from Laos (BSRU-AA-1224) (F), male from Laos (BSRU-AA-1236) (G–K), and male from Thailand (BSRU-AB-4358) (L) H–J male genitalia in dorsal, ventral, and lateral view K male S8 L apical sterna of male in ventral view. Scale bars: 2 mm (D); 1 mm (A–C, E–G); 0.5 mm (H–L).

39 (16♀, 23♂). India: Karnataka: Bangalore, GKVK, 1♀, 2 Apr. 1982, Ghorepade, 1♂, 15 Apr. 2013, Girish, (UAS); Mysore, 1♀, 19 Apr. 2009, 2♀, 16 Apr. 2009, 1♂, 5 Apr. 2009, Dhanyavathi. (UAS); 1♂, Mandya, 1 May 2014, Veereshkumar (UAS; same specimens as Kumar et al. 2017); 1♂, Coimbatore, 3 Mar. 1950, P. Susai Nathan [Eoanthidium semicarinatum Past. D.B. Baker det. 1982 / D.&M. Baker collection KUNHM#2004-en-004 / SEMC0975139] (SEMC25); 1♂, Madras State Coimbatore (alt. 1,400 m) Apr. 1962, P. Susai Nathan [E. semicarinatum det. Pasteels 1969 / PARATYPE / R.M.N.H.B. 24.136] (RBINS113); 1♂, Hisar, 15 May 1986, A. Rahman [D.&M. Baker collection KUNHM#2004-en-004 / SEMC0975140] (SEMC28); 1♀, Karnataka Malaksamudra Tank, 2 Mar. 1984, K. Ghopada [B21 / Ghorpade collection Bangalore / E. (Hemidiellum) semicarinatum det. C.G. Michener / SEMC1321747 KUNHM-ENT] (SEMC41); Pondicherry State Karikal, Mar. 1962, P. Susai Nathan, 1♀ [E. semicarinatum n. sp. Pasteels det. 1969 / HOLOTYPE / RMNH.INS 943212) (NBC001), 1♂ [E. semicarinatum n. sp. J.Pasteels det. 1969 / ALLOTYPE / PARATYPE / RMNHS.INS 943188] (NBC033), 1♂ [E. semicarinatum n. sp. J.Pasteels det. 1969 / PARATYPE / RMNHS.INS 943189] (NBC034); Laos (new record): Champasak, Si Phan Don, 3♀, 11♂, Don Det, 20 Jan. 2015, N. Warrit et al. (CUNHM: BSRU-AA-1220–1222, 1224–1226, 1228–1230, 1232–1234, 1236–1237); 1♀, KHONG ISLAND [= Don Khong], 25 Oct. 2008, D.W. Baldock, E. Popov Hemidiellum Pasteels riparium (Cckll.) det. Risch, 2008 (NHMUK: BMNH-ENT-2017-196 (ACQ)); Myanmar (new record): 1♀, Dawei city (13°50.933'N, 98°9.647'E, alt. 15 m), 3 May. 2018, N. Warrit et al. (CUNHM: BSRU-AA-6896); Pakistan: Punjab, Lahore, 2 May 1979, P.H.B. Baker, 1♂, [E. semicarinatum Past. D.B. Baker det. 1982 / D.&M. Baker collection KUNHM#2004-en-004 / SEMC0975141] (SEMC26), 1♂, [D.&M. Baker collection KUNHM#2004-en-004 / SEMC0975140] (SEMC27), 4♀, [D.&M. Baker collection KUNHM#2004-en-004 / SEMC0975143–0975146] (SEMC29–32); Thailand: 1♀, type, nan. Siam Jan. 7. (Cockerell) [= Nan province, 7 Jan, year is not indicated on the label, but Cockerell’s work was published in 1929], Dianthidium riparium TYPE: Ckll., B.M. TYPe HYM. 17?? [?? = may be “01” but is difficult to read] 1939, Brit. Mus. 1933-567 (NHMUK 014026126); 1♂, Chiang Mai, Chiang Dao District, Chiang Dao Wildlife Sanctuary (19°24'53.2506"N, 98°54'53.2218"E, alt. 541 m) specimen from TIGER project T-5776, 19/25 Feb 2008, Songkran & Apichart (CUNHM: BSRU-AB-4358); 1♂, Lampang, Mueang Pan District, Chae Son National Park (18°49'44.2488"N, 99°28'15.1026"E, alt. 509 m), specimen from TIGER project T-5413, 7/14 Apr 2008, Boonruen & Acharaporn (CUNHM: BSRU-AB-4360).

China (Yunnan, new record), India (Haryana: Hisar, Karnataka: Bangalore, Koppala, Mysore, Mandya, Tamil Nadu: Karikal, Coimbatore, Punjab: Pathankot), Laos (Champasak, new record), Myanmar (Dawei, new record), Pakistan (Punjab: Lahore), Thailand (Chiang Mai (new record), Lampang (new record), Nan (new record)).

The species exhibits pale yellow maculation, remarkably on supraclypeal area (which is reduced medially into a unique shape or absent (Fig. 6), as shown for Laotian, Myanmarese, Thai holotype of Dianthidium riparium Cockerell, 1929 and Chinese D. chinensis Wu, 1962), two paramedian yellow stripes on the scutum, and wide yellow bands on all terga which is often a little disrupted at the median on T1–T5 and also T6 in males. In males, T7 with a broadly rounded lateral lobe and a small median notch with cutting end. Genitalia as in Fig. 6H–J, gonostylus in ventral with inner swollen base, apodeme of penis valves extremely extended.

The record of Chinese element (Wu 1962) mentioned “Eupatoreae sp.” (today recognized as Eupatorieae, Asteraceae) from China. Noteworthy, the group includes the globally invasive “Tropical whiteweed” (Ageratum conyzoides L.), that also widely distributed in South China and locally used as a biocontrol plant to enhance the productivity of farmland (Huang et al. 2011). The study from India by Gorain et al. (2012) reported the visitation of Eoanthidium punjabense on "ghaf" tree (Prosopis cineraria (L.) Druce (Fabaceae)).

Although the specimens from China, Laos, Myanmar, and Thailand are different in their coloration compared to the type bearing the name Eoanthidium (Hemidiellum) semicarinatum, some characters and male genitalia are unique among the genus, and obviously comparable (see also the figures in Wu 1962; Pasteels 1972; Kumar et al. 2017). The female of “Dianthidium riparium” was described by Cockerell (1929), but he did not refer to its juxta-antennal carina, the main character of the genus Eoanthidium, and Eoanthidium was designated later (Popov 1950). Likewise, the description and the illustrations of Eoanthidium (Eoanthidium) chinensis (Wu, 1962) (Wu 1962: figs 23–26; 2006: fig. 66) and photographs of further material held in IZCAS provided by Ze-Qing Niu are adequate to synonymize this taxon with Eo. riparium.

When compared with “Eo. semicarinatum” specimens from India and Pakistan, it is evident that the individuals from Southeast Asia and China (Yunnan) are larger and darker, and tend to come with a reduction in pale yellow facial maculation in supraclypeal area, frons, and on mesepisternum, scutum, and scutellum (Fig. 7). Most of the paramedian band on the scutum is obscure, narrow, and not connected to the anterolateral mark, while the yellow mark on female hindlegs is not fully extended as in Indian and Pakistani specimens, thus, making the apical part of tibia, basitarsus, and the most of tarsi black. The pattern in most of the Laotian and Myanmarese specimens have a distinct reduction of the supraclypeal mark in the middle. A specimen from Khong Island (Fig. 6E) shows more reduction, evidenced by the disruption in the middle of the stripe below the antennal socket, coupled with an additional apical disruption noticed on the clypeus. For the female holotype of Dianthidium riparium from Nan, Thailand, the maculation is more reduced, clearly absent in its supraclypeal area (Fig. 6B), and thus has a strong disruption on the clypeus.

Figure 7. 

Illustration of Eoanthidium (Hemidiellum) riparium (Cockerell, 1929) facial maculation mapped according to their geographic locations (blue boxes indicate Indian-Pakistani morphs, reddish boxes indicate Indochina morphs; a morph marked with asterisk is illustrated based on Wu 1962: fig. 22).

Individuals from the eastern part of the distribution (China, Laos, Myanmar, and Thailand) have a black background color of the integument with yellow markings (Fig. 8). The same is true for the populations in southern India. However, a male from northern India (Hisar) has a reddish brown background color of meso- and metasoma; the ground color of the head is black (face) and reddish brown (vertex). Individuals from Pakistan take an intermediate position, characterized by a scutum with a black background and the abdominal terga with a reddish brown background color (Fig. 8). No sexual differences were noted in the distribution of this pattern, i.e., both sexes are paler in Pakistan (4 females, 2 males) and north India (1 male), while the eastern populations are dark in both sexes.

Figure 8. 

Male of Eoanthidium riparium (Cockerell, 1929) from different regions A–C dorsal view of individuals from South India (Karnakata), Pakistan (Panjab), and North India (Hisar, Haryana) respectively D face of a male Eoanthidium riparium from Pakistan (SEMC27). Note the change in the ground color from black (A) across reddish brown on terga and black on scutum (B) to entirely reddish brown (C). Also, note the shape of the reddish apical margin of the clypeus (black arrows) which is similar to the drawing of Gupta (1993: fig. 65) for Eo. punjabense.

Additionally, specimens from India and Pakistan have a much larger paramedian mark on the scutum, often extending to connect with the anterolateral mark, and generally they display more extensive maculations. The female almost has a fully yellow hindleg, sometimes with the black left on the tarsi and parts of basitarsus. Such individuals with richer yellow maculation are typical for Pakistan. Some females from southern India (including those shown by Kumar et al. 2017: figs 7, 8) have a greater reduction in the yellow clypeal mark, resulting in a complete black stripe in the median area, whereas other specimens come with fully yellow without any black disruption.

For some West Palaearctic Eoanthidium and Rhodanthidium species, Kasparek (2019b, 2020, 2021) reported regional variations in the color pattern and discussed the possibility that the “darker” forms might be a result of adaptation to solar radiation. While in some cases, color variation follows geographical clines, there seems to be reproductive isolation between pale and dark forms in other cases. We observed a clear geographical pattern of color variants in Eo. riparium, but also intermediate forms in Pakistan (see Fig. 8), indicating that there is no reproductive isolation.

In addition, Eoanthidium punjabense Gupta & Sharma, 1993 is established here as a new synonym of Eo. riparium. Gupta (1993) noted that these two species are distinguished by the form of the apical margin of the clypeus, the shape of genitalia, color pattern of the integument and body size. While Gupta (1993) solely relied on Pasteels’ (1972) description, the larger material examined by us as well as the examination of Pasteels’ type material enabled a better understanding of the range of variation. The reddish apical margin of the clypeus is crenulated and somewhat irregularly formed. Our material includes one male with two protrusions (Fig. 8D), very similar to those shown by Gupta (1993: fig. 65). With respect to differences in genital morphology, Gupta (1993) may have been misguided by the incomplete drawings by Pasteels (1972). Body size of Eo. punjabense was found to be within the variability range of Eo. riparium.

As a cleptoparasitic bee, Euaspis has a distinct median longitudinal carina (Fig. 9B), juxta-antennal carina, and often comes with reddish metasoma. Baker (1995) revised the Asiatic species and Tran et al. (2016) noted and discussed three species from Vietnam. Additional material is still crucially required to prove and justify some problematic species in this genus.

Figure 9. 

Females of Euaspis aequicarinata Pasteels, 1980 (BSRU-AB-4120) A mesosoma including the scutellum B face C, E S6 D lateral habitus. Scale bars: 2 mm (D); 1 mm (A–C, E).

(1♀, 2♂). Thailand: 1♀, Chiang Mai (new record), Chom Thong District, Ban Luang Subdistrict, Doi Inthanon National Park, Ban Mae Klang Luang. (18°32'17.9"N, 98°32'49.6"E, alt. 1,057 m), 30 Aug. 2021, on Coleus scutellarioides (L.) Benth. [Lamiaceae], T. Srimaneeyanon et al. (CUNHM: BSRU-AB-4120); 2♂, Phayao (new record), Mueang District, Maeka Subdistrict, Phayao University (19°1'31.45"N, 99°53'24.17"E, alt. 558 m), 1 Jun 2012, W. Suwannarak et al. (CUNHM: BSRU-AA-4445, 4462).

China (Yunnan), Indonesia (Java), Laos (Vientiane), Malaysia (Negeri Sembilan, Borneo: Sabah, Sarawak), Thailand (Chiang Mai (new record), Nakhon Ratchasima, Phayao (new record), Surat Thani)), Vietnam (Kon Tum, Hoa Binh).

Typically for Euaspis, Eu. aequicarinata has a black body with a reddish metasoma, and a median carina and a juxta-antennal carina are present on its face. This is the only species that has a distinct longitudinal carina on the clypeus, while the sculptures are confluent. Pale yellow patches are found on the lateral margin of scutellum and posterior margin of axilla (absent on axilla for female in this study, in contrast to the monochrome pictures in Baker (1995: fig. 30); compared to Eu. strandi, the band is more restrict and more yellowish. Female S6 obtuse, with distinct elevated basal platform (Fig. 10C, E). Male S5 with median subcircular hyaline area and median tooth, genitalia with an apical lamina which is longer than 2× its width.

Figure 10. 

Females of Euaspis polynesia Vachal, 1904 (BSRU-AA-4453) (A–D) and Euaspis strandi Meyer, 1922 (BSRU-AA-4470) (E–H) A, E lateral habitus B, F face C, G mesosoma including the scutellum D, H S6, with a white dash line indicating boundary of the median elevated area in the left. Scale bars: 2 mm (A, C, E, G); 1 mm (B, D, F, H).

Coleus scutellarioides (L.) Benth. (Lamiaceae).

As mentioned in Soh et al. (2016), the status of male Eu. aequicarinata is not confirmed since the male allotype was designated from Surat Thani, Thailand, while originally, the female holotype is from Sabah (in Borneo), Malaysia. For this reason, there is currently no proof that the male is associated with the holotype regardless of the fact that they are similar in clypeal form and mesosomal maculation. Also, Pasteels (1980) did not mention any male genitalia or associated structures. Baker (1995) subsequently rectified the erroneous type locality in his key for Oriental Euaspis species, noting that Eu. aequicarinata should have an apical lamina longer than twice its width.

43 (20♀, 23♂). Thailand: 1♀, Chainat (new record) [with obscured label] (KKIC); 1♀, Chanthaburi, Makam District, 25 May 2015, N. Chattanabun (CUNHM: BSRU-AA-4458); Chiang Mai, Chom Thong District, Ban Luang Subdistrict, Doi Inthanon National Park, Ban Mae Klang Luang, Tourist Station, 1♀, (18°32'2.8"N, 98°32'55"E, alt. 1015 m), 16 Jun. 2019, N. Warrit et al., on Cuphea hyssopifolia K. [Lythraceae] (CUNHM: BSRU-AA-7927); 1♀, (18°32'28.4"N, 98°32'57.2"E, alt. 1020 m), 26 Oct. 2020, T. Srimaneeyanon et al. (CUNHM: BSRU-AB-1372), Chiang Mai, Chom Thong District, Ban Luang Subdistrict, Doi Inthanon National Park, Ban Mae Klang Luang. 2♂, (18°32'12.17"N, 98°32'48.99"E, alt. 1,056 m), 17 Feb. 2021, Srimaneeyanon et al. (CUNHM: BSRU-AB-2810, 2843), 1♀ 2♂, (18°32'29.7"N, 98°32'1.2"E, alt. 1,033 m), 01:00–05:00PM, 7 May 2021, T. Srimaneeyanon et al. (CUNHM: ♀ BSRU-AB-3459, ♂ BSRU-AB-3548, 3550), 1♀ 2♂, (18°32'29.6"N, 98°33'01.4"E, alt. 1,012 m), 30 Aug. 2021, T. Srimaneeyanon et al. (CUNHM: ♀ BSRU-AB-4153, ♂ BSRU-AB-4154, 4155). Chiang Mai, Chom Thong District, Ban Luang Subdistrict, Doi Inthanon National Park, Mae Klang Waterfall, 1♀, (18°29'40.70"N, 98°40'01.95"E, alt. 330 m), 18 Feb. 2021, T. Srimaneeyanon et al. (CUNHM: BSRU-AB-3056), 1♀, (18°29'33.2"N, 98°40'13.1"E, alt. 319 m), 8 May 2021, T. Srimaneeyanon et al. (CUNHM: BSRU-AB-3320). 1♀, Chiang Mai, Mae Rim District, Pong Yaeng Subdistrict, Queen Sirikit Botanic Garden, 21 Aug. 2016, Aerial net, N. Chatthanabun (CUNHM: BSRU-AB-1782); Kanchanaburi (new record), 1♀, Tha Sao Dist., Hellfire pass interpretive centre (14°21'4.1472"N, 98°57'23.5476"E, alt. 240 m), 17 Dec. 2021, S. Deowanish et al. (CUNHM: BSRU-AB-5493). 1♀, 1♂, Sai Yok District, Wang Krachae Subdistrict (14°11'6.5724"N, 99°3'6.9258"E, alt. 102.3 m), 24 Jun. 2016, N. Warrit et al. (CUNHM: BSRU-AA-4480, 4483); 1♂, Mukdahan (new record), Mueang District (16°34'11.4630"N, 104°43'47.1426"E, alt. 139 m), 18 Jan. 2017, N. Warrit et al. (CUNHM: BSRU-AA-4903); Nakhon Pathom (new record), 1♀, Kamphaeng Saen District, 8 Jul. 2003, Subat (KKIC). 1♀, 21 Nov 2002, Pornwat (KKIC). 2♂, (13°44'58.3908"N, 99°52'33.1242"E, alt. 14 m), 10 Jul. 2015, N. Warrit et al. (CUNHM: BSRU-AA4466, 4467). 2♀, KU Kamphaengsaen Campus, Insect Park (14°02'18.1500"N, 99°58'56.5016"E, alt. 3 m), 29 Jul. 2015, N. Warrit et al. (CUNHM: BSRU-AA-4476, 4477); 6♂, Phayao (new record), Mueang District, Maeka Subdistrict, Phayao University (19°1'31.45"N, 99°53'24.17"E, alt. 558 m), 1 Jun. 2012, W. Suwannarak et al. (CUNHM: BSRU-AA-4446, 4448, 4450, 4463, 4464, 4465); 1♀, Phetchabun (new record), Lomsak District, Bungkla Subdistrict (18°15'N, 103°58'E, alt. 162 m), 18 Oct. 2009, K. Attasopa & P. Phukphume (CUNHM: BSRU-AA-4442); 1♀, Phetchaburi (new record), Kang Kra Chan District, 18 Apr. 2012, C. Rungsri (CUNHM: BSRU-AA-4443); Ratchaburi (new record), 1♀, Jom Bung District, 26 May 2012, N. Warrit & W. Suwannaruk (CUNHM: BSRU-AA-4453). 2♂, Ratchaburi, Suan Phueng District, Pasutara resort (13°31'5.9226"N, 99°20'51.6366"E, alt. 104.71 m), 2 Aug. 2019, P. Senawong et al. (CUNHM: BSRU-AB-0764, 0765); Saraburi (new record), 1♂, Kaeng Khoi District, Chula-Saraburi (14°31'3"N, 101°1'41"E, alt. 43 m), 15 Aug. 2015, N. Warrit et al. (CUNHM: BSRU-AA-4481). 1♀, (14°31'23.4300"N, 101°1'43.5216"E, alt. 52.89 m), 13 Oct. 2018, N. Warrit et al. (CUNHM: BSRU-AB-0154); 2♂, Trang, Na Yong District (7°33'8.0892"N, 99°46'33.6072"E, alt. 24 m), 11 Jun. 2015, N. Warrit et al. (CUNHM: BSRU-AA-4457, 4459); Ubonratchathani (new record), 1♂, Khueng Nai District, Ko Ae Subdistrict, Ubon Rachathani Rajabhat Univ. Faculty of Agriculture, 30 Aug. 2020, P. Traiyasut et. al. (CUNHM: BSRU-AB-1704), 1♂, Na Chaluai District, Phu Chong Na Yoi National Park (14°26'4.98"N, 105°15'31.04"E, alt. 269 m), 23 Jan. 2015, N. Warrit et. al. (CUNHM: BSRU-AA-4460), 1♀, Na Chaluai District, Phu Chong Na Yoi National Park, Pa Lan Pa Chad (14°26'5.36"N, 105°15'39.92"E, alt. 280 m), 27–29 Sep. 2020, P. Traiyasut et. al. (CUNHM: BSRU-AB-1704).

China (Anhui, Fujian, Gansu, Guangdong, Hebei, Hunan, Jiangsu, Jiangxi, Shangdong, Xizang, Yunnan, Zhejiang), Hong Kong, Indonesia (Bali, Bangka Island, Engano Island, Java, Maluku Islands [Ambon, Buru, Kai islands], Sebesi Island, Sumatra, Sulawesi), India (Arunachal Pradesh), Japan (Okinawa Prefecture), Laos (Xiengkhouang), Malaysia (Kedah, Kelantan, Melaka, Penang, Perak, Selangor), Myanmar (Shan State, Tenasserim, Yangon), Nepal (Kathmandu), Philippines (Luzon, Mindanao), Singapore, Taiwan (Pingtung), Thailand (Chiang Mai, Chainat (new record), Kanchanaburi (new record), Loei, Mukdahan (new record), Nakhon Pathom (new record), Pattani, Phayao (new record), Phetchabun (new record), Phetchaburi (new record), Ratchaburi (new record), Saraburi (new record), Satun, Songkhla (new record), Surat Thani, Trang (new record), Ubon Ratchathani (new record)), Vietnam (Bak Kan, Dak Lak, Dak Nong, Dien Bien, Hoa Binh, Phu Tho, Son La, Thanh Hoa, Vinh Phuc).

Most of the previous records were documented by Baker (1995) and Pasteels (1980). The species is widely distributed in Eastern Asia, especially in South-east Asia, where Soh et al. (2016), Tran et al. (2016), and Ghosh et al. (2023) reported additional distribution records.

This Euaspis species has an entirely reddish metasoma, while the prosoma and mesosoma are all black; face with longitudinal carina and a median longitudinal ridge; clypeus with uniform punctation; punctures on the scutellum looser and coarser than on the scutum; scutellum large, strongly produced posteriorly, apicomedially with a depressed area; female S6 acute, with a median carina, without a distinct basal area (Fig. 10D); male S6 without emargination at the margin; male genitalia with the apical lamina with a length less than twice its width.

A female collected from Chiang Mai was wandering on the inflorescences of “Tropical whiteweed” Ageratum conyzoides L. (Asteraceae), “Black-Jack” Bidens pilosa (L.) Benth. (Asteraceae), and “Mexican heather” Cuphea hyssopifolia K. (Lythraceae). For Singapore, Soh et al. (2016) reported that Eu. polynesia visits the flowers of Averrhoa carambola L. (Oxalidaceae), Grammatophyllum speciosum Blume (Orchidaceae), Muntingia calabura L. (Muntingiaceae), and Premna serratifolia L. (Lamiaceae). They also mention Cordia cylindristachya (Ruiz & Pav.) Roem. & Schult. (Boraginaceae) and Antigonon leptopus Hook. & Arn. (Polygonaceae), of which the latter genus was also given by Baker (1995). The recent study from India by Ghosh et al. (2023) found Eu. polynesia nectaring on Fagopyrum esculentum Moench (Polygonaceae).

Bingham (1897) noted a single male of Eu. polynesia accessing the nest of Megachile disjuncta (Fabricius, 1781). Since the female generally takes on the parasitizing task, this must not be the direct act of the invasion for parasitisation, but the reason remains unknown.

Euaspis polynesia is the most common anthidiine bees in Thailand, exhibiting a size range, with the females ranging 9.0–13.1 mm and the males 6.2–12.1 mm. As a cleptoparasitic bee, its occurrence seems to follow the distribution of its hosts, especially Megachile disjuncta (see Baker 1995), which is very common and widely distributed in Thailand. Thus M. disjuncta is a megachilid species with most individuals curated at the CUNHM (i.e., 102 specimens curated, from 905 Megachilidae specimens). All 11 Euaspis localities in the CUNHM database (Nalinrachatakan et al. 2021a) have been associated with bees from the genus Megachile (at least 7 subgenera were identified). Aethomegachile (8 localities) and Callomegachile (8) contributed the most, e.g., M. (Ca.) umbripennis (6), M. (Ca.) disjuncta (5), and M. (A.) laticeps (6). Other notable species belonged to M. (Creightonella) fraterna (5), and another cleptoparasitic bee genus Coelioxys was also found in eight of 11 occasions. This information shows that both Euaspis and Coelioxys may have a wide range of their candidate host, and there is the possibility of overlap or of having an evolutionary pressure on each other that cannot be ignored, as both genera were reported to come with different brood-parasitizing strategies (Litman et al. 2016; Litman 2019).

A probable new species of Euaspis from Singapore (Soh et al. 2016) is superficially similar to Eu. polynesia, but mostly differs in the terminalia, apical terga coloration, and with a pale mark on the scutellum margin, while their genitalia are superficially similar. Further studies and molecular evidence are required to resolve this taxonomic conundrum.

(2♀). Thailand: Phayao (new record), Mueang District, Maeka Subdistrict, Phayao University (19°1'31.45"N, 99°53'24.17"E, alt. 558 m), 1 Jun. 2012, W. Suwannarak et al. (CUNHM: BSRU-AA-4444, 4470).

China (Yunnan, “Kinpin”: Wu 1962: 168 as Parevaspis bakeri), Thailand (Nakhon Ratchasima, Phayao: new record), Philippines (Mindanao).

Euaspis strandi has a reddish metasoma, whereas the rest of the body is black, with a remarkable pale yellow stripe on the mesonotum (i.e., axilla and scutellum with pale yellow marginal band); clypeus with coarse, somewhat irregular punctures (Fig. 10F); punctures on scutellum looser and coarser than on scutum; scutellum large, produced posteriorly with a small shallow median emargination; female apical margin of S6 obtuse, with an enlarged basal platform which contributes ~ 1/2 of the sternal length (Fig. 10H); male was purposed by Viereck (1924) as without mesosomal yellow stripe, apical lamina of gonoforceps with a length of more than twice its width.

Sindora siamensis Teijsm. ex Miq. (Fabaceae) is associated with the female collected from Nakhon Ratchasima, Thailand (Baker 1995).

In Thailand, Eu. strandi was reported from Sakaerat, Nakhon Ratchasima province in 1995 (Baker 1995). Two females examined from Phayao province were quite large (11.4 mm and 11.5 mm) compared with Eu. polynesia, which varies considerably in size.

The female individual was not observed in this study. Previously, two male specimens had been designated, the first one by Meyer (1922) as syntype together with a female specimen, and the second by Viereck (1924) as Parevaspis strandi. Both specimens were redescribed and discussed by Baker (1995), and the locality of Meyer’s syntype was corrected and the male was selected to be a lectotype. Therefore, the validity of the female identity is still ambiguous, also mentioned in Baker (1995): syntypes were mislabeled, collected without any notes to confirm that they come from the same locality, and are doubtfully paired since the notable character does not match, i.e., an absence of the marginal mark on scutellum and axilla, which is noticeable in the female.

1♀. Thailand: Chumporn (new record?), Sawi District, Na Sak Subdistrict (10°10'10.7"N, 98°56'50.5"E), 1 Jun. 2021, Suntaree Kanchananiyom. (PMCS: SK-BSRU-0068 [association number with CUNHM]).

Indonesia (Bacan province in north Maluku [= Batjan (in Dutch) in Baker (1995)], Thailand (Chumporn, new record?).

This female Euaspis aff. wegneri has a typical black body and reddish metasoma, with a pale yellow stripe on the mesonotum (Fig. 11B) resembling Eu. strandi (pale yellow marginal band on scutellum, more minute on axilla). Clypeus moderate in size, somewhat confused punctures, while the punctures on the scutellum are coarser than on scutum. Female S6 (Fig. 11D, E) subacute with obscured basal platform contributing almost half of the length of S6 while the apical half of S6 forming faint median carina, lateral margin with small, obscured, blunt teeth. In contrast, yellow maculation in mesosoma is absent in the holotype of Eu. wegneri (see Baker 1995: figs 24, 28, 31) and has more fine and dense punctures on the scutum and scutellum, while S6 seems to be more acute.

Figure 11. 

Female of Euaspis aff. wegneri Baker, 1995 A face B dorsal habitus C lateral habitus D, E S6. Scale bars: 2 mm (B, C); 1 mm (D, E); 0.5 mm (A).

Unknown.

Euaspis wegneri has been described on the basis of a single female and has never been reported after that. The holotype of Eu. wegneri represented with monochrome digitization in Baker (1995: figs 24, 28, 31, for S6, face, and mesonotum, respectively) arguably has a black mesosoma, with more fine and dense punctures on scutellum compared to scutum. Here, we decided to put this Thai specimen as Eu. aff. wegneri since the other characters are comparable especially on S6 which is distinctive for each Euaspis species. Other characters can be considered variations, although S6 of the holotype seems to be more acute. With the possibly new species noted in Soh et al. (2016) (also noted in the Eu. polynesia section above), we consider that examination of more specimens coupled with molecular analyses are needed in order to resolve the true identity of these enigmatic specimens.

This genus can be easily distinguished by its explicit robust body, closed scutoscutellar suture (Fig. 12C), and lamellated preoccipital carina, omaular carina, and scutellum (see Fig. 12C, E). Eardley and Griswold (2017) revised 16 Afrotropical species of this genus from 18 described species, the two remaining species are in the subgenus Trichanthidium, including a one-time discovered Pachyanthidium himalayense (Gupta & Sharma, 1993) and Pachyanthidium lachrymosum (Smith, 1879) discovered from India and Chaiyaphum, Thailand (Bingham 1897; ITIS 2008; Tadauchi and Tasen 2009; Kumar et al. 2017).

Figure 12. 

Pachyanthidium (Trichanthidium) lachrymosum (Smith, 1879) A female face B male face C male dorsal habitus D female metasoma E male lateral habitus F, G male metasoma. Scale bars: 2 mm (C, E); 1 mm (A, B, D, F, G).

(24♀, 3♂). India: 1♀, Bombay Dist. [= Mumbai, Maharashtra], B.M. TYPE HYM.17a 1866, (syntype) (NHMUK 014026059); Karnataka: Mysore, 1♀, 17 Apr. 2009, Dhanyavathi; “Yerbahalli” [must be Yerehalli, Mysore], 1♀, 29 Jul. 2014, Revanasidda (UAS); Bangalore, GKVK, 1♀, 29 Jul. 2014, Veereshkumar, 1♀, 25 Jun. 2014, Sunil, 1♀,18 Nov. 2014, Zameer, 2♂, 29 Apr. 2010, Arathi (UAS); Tamil Nadu: 1♀, Coimbatore, 5 Sep. 1950, P S Nathan (UAS); Thailand: 1♂, Chiang Mai (new record), Chom Thong District, Ban Luang Subdistrict, Doi Inthanon National Park, Ban Mae Klang Luang (18°32'29.7"N, 98°32'01.2"E, alt. 1,033 m), 7 May 2021, on Bidens pilosa (L.) [Asteraceae], T. Srimaneeyanon et al. (CUNHM: BSRU-AB-3551); 2♀, Kamphaeng Phet: Pang Sila Thong District, 7 Aug. 2015, N. Warrit et al. (CUNHM: BSRU-AA-4478, 4479); 6♀, Khon Kaen, Phu Wiang District, 26 May 2016, N. Warrit et al. (CUNHM: BSRU-AA-4484–4489); 1♀, Phayao, Mueang District, Phayao University (19°1'41.9334"N, 99°52'59.9730"E, alt. 493.41 m), 8 Oct. 2019, N. Warrit et al. (CUNHM); 8♀, Phetchabun, Namnao District, 19 Jun. 2017, N. Warrit et al. (CUNHM: BSRU-AA-4649–4656).

India (Karnataka (Bangalore, Mysore), Malabar (as per Bingham (1897), must refer to “Malabar coast” on southwest India), Maharashtra (Mumbai), Tamil Nadu (Coimbatore), Malaysia (Perak), Myanmar (Tenasserim), Thailand (Chaiyaphum, Chiang Mai (new record), Kamphaeng Phet (new record), Khon Kaen (new record), Phayao (new record), Phetchabun (new record)).

The records from Smith (1879) based on both sexes were noted to come from “Bombay district”, whereas Bingham (1897) who later revise Smith’s work, additionally mentioned “Malabar” and “Tenasserim” without any further information, also without any note if the additional material was examined. Most of the records from India are already listed by Kumar et al. (2017). Friese (1914) reported a male from Malaysia. In Thailand, Tadauchi and Tasen (2009) reported the species from Phu Khiao Wildlife Sanctuary in Chaiyaphum province.

Pachyanthidium lachrymosum can be distinguished from other congeneric species by its black body with a white lateral band of short white hairs on the metasoma; lamellate parts are often translucent reddish brown to black; eyes with sparse short hairs; mandibles with four teeth; arolia absent; male similar to females but mostly differs in the presence of the arolia, three mandibular teeth, lateral spines on T3–T6, and a tridentate T7 (Fig. 12F, G), also noted in Bingham (1897) and Kumar et al. (2017). Pachyanthidium lachrymosum also exhibits a robust, lamellate preoccipital ridge and an omaular carina, which are typical for Pachyanthidium.

Bidens pilosa (L.) (Asteraceae) (this study), Leucas aspera (Willd.) Link (Lamiaceae) (Kumar et al. 2017).

The other four species of Pachyanthidium (Trichanthidium) were revised by Eardley and Griswold (2017). Pa. lachrymosum is the only species that does not have any integument maculation and has not been reported from the Afrotropical region. When compared with Indian specimens from both Kumar et al. (2017) and Smith (1879), we notice that the white hair patch on the metasoma appears to be more clumped and dense in Indian specimens, while in the Thai specimens the hairs seem looser and the patch more extended. The patch on the scutum is absent in some Thai individuals and white body patches are absent in some Indian specimens.

All specimens in CUNHM are females. Promisingly, two individuals are full of pollen trapped by the facial pubescence (Fig. 12A); thus, with their broad facial area, Pa. lachrymosum may also can gather pollen by rubbing it with its face (see also Portman et al. 2019; Kasparek et al. 2022).

Kumar et al. (2017) provides a note on Indian Pa. lachrymosum flight period (April, June, July, and November) and floral visitation (see above). Our specimens from Thailand were collected in May, June, and August.

Pseudoanthidium commonly has a tentorial pit placed below the connection of the subantennal suture and the epistomal suture (Michener 2007). The female mandible has more than four teeth, and the terga are without an apically depressed area (see Fig. 13E; Litman et al. 2016). As a very broad, ill-defined complex group, the South East Asian fauna is represented by only one subgenus, Pseudoanthidium s. str.

Figure 13. 

Pseudoanthidium orientale (Bingham, 1897) [showing Mae Hong Son female (BSRU-AA-1240) (A–D), and male (BSRU-AA-1241) (E–K)] A, H dorsal habitus B, G lateral habitus C, F face D female T6 E male T7 I male S5 J S8 K male genitalia in lateral (left), dorsal (middle) and ventral (right). Scale bars: 2 mm (A, B, G, H); 1 mm (C–F); 0.5 mm (I–K).

(10♀, 3♂). Laos (new record): 3♀, Champasak, Si Phan Don, Don Det, 20 Jan. 2015, N. Warrit et al., (CUNHM: BSRU-AA-1223, 1227, 1231); 1♀, Pakse, Bolaven plateau, Phu Suam Water Fall (15°16'44"N, 105°53'23"E), 19 Jan. 2015, N. Warrit et al., (CUNHM: BSRU-AA-1235); Thailand: Chiang Mai, 1♀, Mae Chaem District, Baan Na Jon (18°42'11.3970"N, 98°16'59.3754"E, alt. 874.93 m), 9 Dec. 2015, N. Warrit et al. (CUNHM: BSRU-AA-1243); 1♀, Chiang Mai, Chom Thong District, Doi Inthanon National Park, (18°32'12.39"N, 98°31'14.44"E, alt. 1,267 m), 16 Feb. 2021, Srimaneeyanon et al. (CUNHM: BSRU-AB-2970); 1♀, Kamphaeng Phet, Mueang District, (16°28'18"N, 99°29'43"E, alt. 10 m), 4 Dec. 2015, C. Thanoosing (CUNHM: BSRU-AA-1252); 1♂, Lampang, Mueang Pan District, Chae Son National Park (18°50'15.0498"N, 99°28'19.5594"E, alt. 451 m), TIGER project T-2922, Malaise trap, 8/14 Dec 2007, Boonruen & Acharaporn (CUNHM: BSRU-AB-4361); 2♀, 2♂, Mae Hong Son, Pang Tong, Under Royal Forest Park 2/ Pang Ung (19°29'58.3008"N, 97°54'42.1014"E, alt. 1,164 m), 10 Dec. 2015, N. Warrit et al. (CUNHM: ♀ BSRU-AA-1239, 1240, ♂ BSRU-AA-1241, 1242); 1♀, Phayao, Mueang District, Maeka Subdistrict, Phayao University (CUNHM: BSRU-AA-1238, Phayao University).

(2023). Thailand: Chiang Mai, San Sai District, San Sai Noi Subdistrict (18°49'08.6"N, 99°01'15.1"E) uploaded by ‘jackychiangmai’ on 14 Jan. 2022 (observation id:104911660); Chiang Rai, Chiang Saen Lake, Viang Yonok Hotel (20°15'42.5"N, 100°02'59.5"E), uploaded by ‘pam-pilombino’ on 27 Jan 2020.

Cambodia (Mondulkiri: Ascher et al. 2016), China (Yunnan), India (Alwar, Poona, Solan, Tolawas, Udaipur), Laos (Champasak (new record), Myanmar (Tenasserim), Thailand (Chiang Mai, Chiang Rai (new record from iNaturalist 2023), Kamphaeng Phet (new record), Lampang (new record), Lamphun (new record from iNaturalist 2023), Mae Hong Son (new record), Phayao (new record)). For the Indian records from Gupta (1993), see Remarks section below.

Pseudoanthidium orientale is a medium-sized bee (6–8 mm) and usually has a black integument with yellow maculations in all tagmata. It has a remarkably pale yellow mark on the paraocular area reaching close to the top of eyes, female mandibles with five or six teeth, rounded scutellum with broad marginal maculation which is medially disrupted, tibia and tarsi yellow except black on the venter, female terga with yellow paramedian maculation on T1–T5 in female, which is more laterally extended on T1 and T2 and nearly rectangular in T3–T5. The male looks superficially similar to the female but has a different dentition of the mandible (i.e., distinctly tridentate, broader especially the inner tooth), and maculation on T6 and T7. Male genitalia broad.

Plants with hairy surfaces (see iNaturalist observation from Lamphun) must be the resources for the nesting material. Also, from iNaturalist image from Chiang Mai, the photographs clearly show the bee wandering on the inflorescence of Antigonon leptopus Hook. & Arn. (Polygonaceae), which is a hairy plant, although there is no direct evidence to this claim. Niu et al. (2021) also noted the floral associations for Ps. orientale including Blumea sp. (Asteraceae), Eupatoreae sp. (Asteraceae), Helianthus annuus L. (Asteraceae), Tephrosia purpurea (L.) Pers. (Fabaceae; originally noted as Tephrosia hamiltoni), and Tridax sp. (Asteraceae; originally noted as “Tridex”).

This species was described by Bingham (1897) as Anthidium orientale, based on a female from Tenasserim, Myanmar. Pasteels (1969) then assigned it to Pseudoanthidium (Paraanthidiellum) Michener, 1948. Gupta (1993) provided both female and male descriptions and illustrations from India, which is designated as Trachusa (Orientotrachusa) orientale. Later, the species was listed as Ps. (Pseudoanthidium) in the World Bees Checklist Project (ITIS 2008). A female Ps. orientale was reported from a monochrome image from Chiang Mai, Thailand (Tadauchi and Tasen 2009), and a male was reported from Bousra, Mondulkiri, Cambodia (Ascher et al. 2016) with photographs. However, the CUNHM male specimens studied here are apparently different from the male descriptions and photographs from Cambodia in lacking the antero-lateral maculation on the scutum. Gupta’s (1993) male description from India also stated that “tergum first with a complete band, T2 and T3 interrupted medially, T4–T7 entirely yellow” which is incongruent to the CUNHM specimens studied here, and also to the photographs of the male from Cambodia; therefore, the Indian specimens need further study.

Pseudoanthidium orientale is superficially similar to Ps. rotundiventre (Pasteels, 1987) from Sri Lanka and India. Kumar et al. (2017) mentioned that these two species were probably referred to the same species. As most of their distinct morphology is similar, the difference is based on color (Fig. 14). First, Ps. rotundiventre has a more extended maculation on the face, the female has an entirely yellow clypeus, and a W-shape maculation on the supraclypeal area. Seven Thai females of Ps. orientale come without supraclypeal mark and show reduction of the clypeal color as a black stigma, while the remaining two from Laos have an entirely yellow clypeus and the supraclypeal mark is only a triangle in the median part. Second, it is remarkable that Ps. rotundiventre comes with more extended maculation on the male terga: the median interruption of the band tends to decrease from base to apex on the metasoma. Specifically, T5 and T6 are nearly uninterrupted and T7 is entirely yellow. The Ps. orientale males show much more consistency in the median interruption of the tergal maculation, making it appear similar to the female. Hence, Gupta’s Ps. orientale male description from India is more congruent to Ps. rotundiventre.

Figure 14. 

Facial and metasomal illustrations of A Pseudoanthidium orientale (Bingham, 1897) and B Ps. rotundiventre (Pasteels, 1980).

As the male genitalia of Ps. orientale illustrated in Gupta (1993: fig. 159) is inadequate to compare with microphotographs of the male genitalia of Ps. rotundiventre (see Kumar et al. 2017: fig. 20C), we used a microphotograph of Thai Ps. orientale genitalia which was prepared and preserved in glycerin. Overall, the genitalia seem to be identical, but the photograph of the genitalia of Ps. rotundiventre is not clear, so the shape and sclerotization of the apodeme of penis valve is hard to compare with that of Ps. orientale (cleared one in Fig. 13K). However, the respective characters do not seem to have much of value in sexual differentiation.From the evidence, it seems that color variation in Pseudoanthidium orientale is variable, and potentially similar to Ps. rotundiventre. At the same time, Ps. flaviventre Cameron, 1897, belonging to the same subgenus, displays much more obvious differences in male genitalia and other external body parts (also see Kumar et al. 2017). Because of the similarities, Kumar et al. (2017) suggested that Ps. rotundiventre is a junior synonym of Ps. orientale, but the types need to be examined before making a final decision.

Finally, there is an observation of wool-collecting behavior of a female of Ps. orientale from Chiang Saen Lake, Chiang Rai, Thailand, reported and observed by Ms. Pamela Piombino [user: ‘pam-pilombino’] on 27 January 2020, and published on iNaturalis.org (iNaturalist 2023). Based on personal communication, the bees landed on a cushion with a mouthful of fiber-ball, wandered around for a few minutes, and eventually flew off without any “active” fiber-collecting behavior. We are not sure if this fiber was collected precisely from the cushion or elsewhere, but this is the first time that fiber-collecting behavior has been observed in this species.

Figure 15. 

Pseudoanthidium orientale wandering around on a cushion with a fiber ball (A–C for cropped close-up). Original photographs taken by Pamela Piombino.

Most of the cleptoparasitic bees of the Anthidiini are attributed to the genus Stelis due to the very diverse morphs. The recent works by Michener and Griswold (1994), Michener (2000, 2007), and Kasparek (2015) for species in Europe, North Africa, and the Middle East provide comprehensive information for Stelis. Female Stelis notably lack scopa and juxta-antennal carina, while the carinae on prosoma and mesosoma can be absent or weakly present. In males, T7 is round, weakly bilobed, or trilobed. The only subgenus discovered in Thailand is Malanthidium (see Nalinrachatakan 2021b), only known by males and can be recognized by its distinct postero-lateral hook on its axilla.

(2♂). Same specimens as in Nalinrachatakan et al. (2021b). Holotype transferred to NHMUK in April 2023.

Thailand (Ubon Ratchathani: Phu Chong Na Yoy National Park).

Since Stelis is a cleptoparasitic bee, its distribution must be in accordance with its host. Noteworthy, the other known species of the subgenus Malanthidium, S. macaccensis (Friese, 1914) is known from Malaysia; thus, Malanthidium is the only subgenus of Stelis present in South East Asian region.

Anthidiellum phuchongense Nalinrachatakan & Warrit, 2021.

Unknown.

With only two males known, some differences between both specimens and their biology were mentioned and discussed in Nalinrachatakan et al. (2021b).

A medium to large, robust, round-edged species, genus Trachusa appears to be sister to the remainder of the tribe Anthidiini (Litman et al. 2016). Recently, Kasparek (2017, 2019a) reviewed the old-world Trachusa and described new Malaysian species, respectively.

(5♀). Thailand: Phitsanulok, Nakhon Thai District, 27 May 2014, N. Warrit et al. (CUNHM: BSRU-AA-4471–4475).

Thailand (Phitsanulok) and Vietnam (Quang Nam).

The species is very close to, or maybe identical to Trachusa vietnamensis. Only the female is known: body large, robust, and black. Bands with yellowish, orangish, or light-brown coloration on the vertex, preoccipital area, anterolateral of scutum, and scutellum, while mesosoma covered in orangish pubescence. The Thai specimens are distinguished from the Vietnamese material by a unique elongate metasoma making it more chalicodomiform, and more limited maculation on the metasoma (fully striped on T1 and T2 of T. vietnamensis, small pale marks on the side of T1 and T2 and minute or absent on T3 and T4 for Thai specimens). The species is also close to T. ovata, from which it differs by the combination of five mandibular teeth, clypeus black with ill-defined shiny median longitudinal line, conspicuous rounded light-brown scutellum which seems darker basally, and head with orangish to light-brown maculations running continuously from the vertex to genal area.

Female: Body length 13.4, 13.3, 13.2, 13.0, 13.3 mm, head width 4.3, 4.3, 4.2, 4.3, 4.1 mm, intertegular distance 3.6, 3.8, 3.8, 3.7, 3.5 mm, respectively. Wingspan 25.0, 25.6, 25.0, 24.7, 24.9 mm.

Head largely black, with light-brown band on vertex running continuously to genal area, lighter on occipital ridge, but not abutting margins of eyes and ocelli. Clypeus (see Fig. 16C) black, slightly convex but shallow depression apically with ill-defined shiny median longitudinal line; middle and apical area with smaller and denser punctures, apical margin slightly crenulate thus looking somewhat emarginate at middle. Surfaces apically covered with sparse short yellow hair that is dense and long. Supraclypeal area black, slightly convex, with shiny median longitudinal line. Mandible broad with apex ~ 1.5× wider than base. Mandibles somewhat dull, black with light-brownish mark on basal area, inner surfaces with hairs. Four mandibular teeth, apical tooth larger than inner. Labrum black, with yellow bristles on its apex. Maxillary palpus three-segmented, black but dark brown on rounded basal segment. Subantennal suture slightly arcuate outwards. Antenna generally brown, scape brown but darker on front, pedicel dark brown to black, flagellum lighter in color on medial front, F1 and F2 brighter than rest. Ocellooccipital distance not more than 1.5× interocellar distance. Head covered with fulvous hair, denser and longer on frons, paraocular area, and lower part of genal area.

Figure 16. 

Female Trachusa aff. vietnamensis BSRU-AA-4473 (A), 4744 (B–E) A lateral habitus B dorsal habitus C face D lateral of metasoma E antennae. Scale bars: 2 mm (A, B, D); 1 mm (C, E).

Mesosoma black, covered with fulvous hair except on pronotum with exposed shiny black median area with coarse punctures. Pronotal lobe strongly carinated, light brown. Mesepisternum black. Omaulus carinated, extending to ventral part of thorax. Scutum laterally carinate, punctures uniform, dense, with light-brown color on anterolateral band, not abutting together in middle. Axilla rounded laterally, entirely light brown. Tegula fulvous with dark patch lining medio-posterior. Scutellum broad, apically round with median emargination, light brown, darker on median triangular basal area.

Wing subhyaline, fuscate, forewing darker at apical margin and marginal cell. Pterostigma brown. Veins dark brown to black; 2^nd recurrent vein abutted to 2^nd submarginal crossvein distally.

Legs covered with short fulvous hairs. Coxae, trochanters, and basal parts of femora dark reddish brown to black; legs otherwise light brown except dark brown on inner surfaces of basitarsus and tarsi, slightly subtle on outer surfaces of hind basitarsus and hind tarsal segments. Apical tarsal segments with apical dark spot. Claw with inner tooth, light brown, apically black. Arolium present, dark brown to black.

Metasoma black. Discs of all terga swollen, with fine dense punctures. Terga covered with short black hairs, lighter to fulvous hairs on T1–T3 lateral surfaces, longer fulvous hairs covering frontal carina of T1. T1 and T2 with small pale lateral patches (Figs 16A, B, D, 17C) with part of obscured thin line extending to median. In some paratypes, these patches can be more or less expressed, tending to form an almost continuous thin but obscure band on disc, and also obscurely found on T3 and T4 in one specimen (BSRU-AA-4471). Scopa pale yellow on S2 and S3, gradually darker on S4, and becoming black on S5 and S6. S1–S6 reddish brown to black, darker apically. T6 with barely visible small median emargination.

Figure 17. 

Female Trachusa aff. vietnamensis (BSRU-AA-4475) A ventral habitus of mouthparts (with removed mandible) B mid tibia C all specimens in dorsal view, showing variation (BSRU-AA-4471–4475, respectively from left to right). Scale bar: 2 mm (C); 0.5 mm (A, B).

Trachusa species have been reported from upper and lower Indochina but with limited materials (Soh et al. 2016; Kasparek 2017, 2019a; Flaminio et al. 2021). It is plausible that the lack of previous records in Thailand, Burma, and Cambodia may be due to limited collecting, in addition to the general rareness of Trachusa bees. This is the first record of Trachusa in Thailand: all specimens are neither complete nor in perfect condition.

Since the species is very close to T. vietnamensis from Vietnam, here we propose that the Thai specimens belong to the same species. The differences in tergal bands on the metasoma may be considered as variation; however, the Thai specimens exhibit a more elongate metasoma. To confirm that both species are indeed the same, DNA barcoding would be useful since the barcode of T. vietnamensis was provided by Flaminio et al. (2021).

Subgeneric placement of Trachusa vietnamensis is still uncertain. Kasparek (2017, 2019a) assigned three species groups in Paraanthidium with their characteristics: interrupta group (female with bright yellow maculations on black, wasp-like), longicornis group (Indomalayan species with female having dull yellow maculation except on the mesosoma), ovata group (female completely without maculation), and the remaining Trachusa xylocopiformis (Mavromoustakis, 1954), for which only the male is known Fukien, China, is large and black except for yellow on lower part of the face.

Trachusa vietnamensis seems to not be congruent with any of these groups, but is closely related to the ovata group by its face, especially in its clypeal shape, and the reduced maculation on the metasoma. Also, the superficially color pattern and almost parallel-sided body form are not congruent with the robust-megachiliform that occurs in all described females of Paraanthidium ; from this, it more resembles the subgenus Orthanthidium from mainland China and Taiwan for which two fairly different species are known: Trachusa formosana (Friese, 1917) and T. cornopes Wu, 2004. Orthanthidium was designated by Mavromoustakis (1953) prominently for its parallel-sided axilla, truncated scutellum, and small spine on the tibial apex. As Orthanthidium is still problematic in its status (Kasparek 2017), future work is still needed.

The astonishing record of another Trachusa species that is completely different from the aforementioned T. aff. vietnamensis has been retrieved from the citizen science database platform iNaturalist (iNaturalist 2023) from Thailand: Chiang Mai, Mueang District, Suthep Subdistrict, Doi Suthep-Pui (18°49'00.5"N, 98°55'26.8"E), observed repeatedly by “jackychiangmai” on 16 Apr, 30 Apr, and 27 May 2022 (observation id: 111730798, 114167310, 119204705 respectively).

Since the identification is restricted to the available photographs, we cannot identify the bee definitively. These observations show multiple Trachusa bees (25+) grouping on a semi-limestone concrete surface (Fig. 18) along with other bees, including Ceratina (Ceratinidia) spp., Chelostoma aureocinctum (Bingham, 1897), possibly Hylaeus sp., and a Halictinae bee (possibly Pachyhalictus or Lasioglossum). This Trachusa species exhibits a large robust body with a round scutellum, while the yellow band on T4–T6 and the yellowish brown patch apically on the leg can also be noticed. Most bees that can be speculated for their sex are usually female based on their pollen-loaded metasomal scopa. Based on the available information, we classify these Trachusa bees to the subgenus Paraanthidium, primarily within longicornis group that contains four described species at present: T. longicornis (Friese, 1902), T. maai (Mavromoustakis, 1953), T. muiri (Mavromoustakis, 1937), and T. rufobalteata (Cameron, 1902) (see discussion above and Kasparek 2017). Collections and information are needed in order to confirm its identity.

Figure 18. 

Groups of Trachusa (Paraanthidium) sp. primarily identified as longicornis group sensu Kasparek (2017), gather with other bee species. Photograph: Jacky Cudon.

Keys to the species of Anthidiine bees in Thailand

Two keys are provided below, one for females and one for males. The keys are modified from Baker (1995), Michener (2007), Engel (2009), Niu et al. (2019), and Flaminio et al. (2021). They both exclude morphospecies known only from citizen science records.