New and little-known species of the genus Sphecodes Latreille (Hymenoptera, Halictidae) from Southeast Asia

Abstract The available information about the cleptoparasitic bees of the genus Sphecodes in Southeast Asia is summarized. Thirty-one species are currently known from this area. Four new species are described: Sphecodes discoverlifei Astafurova & Proshchalykin, sp. nov. (Laos), S. engeli Astafurova & Proshchalykin, sp. nov. (Laos, Vietnam), S. ilyadadaria Astafurova, sp. nov. (Indonesia), and S. pseudoredivivus Astafurova & Proshchalykin, sp. nov. (Laos). Nine species are newly recorded from South East Asia: S. chaprensis Blüthgen, 1927 (Laos), S. howardi Cockerell, 1922 (Malaysia, Myanmar, Thailand), S. kershawi Perkins, 1921 (Indonesia, Malaysia, Myanmar, Thailand), S. laticeps Meyer, 1920 (Thailand, Vietnam), S. montanus Smith, 1879 (Laos), S. sauteri Meyer, 1925 (Laos), S. sikkimensis Blüthgen, 1927 (Laos, Myanmar), S. simlaensis Blüthgen, 1924 (Laos), and S. turneri Cockerell, 1916 (Laos). Based on type specimens, new synonymies have been proposed for Sphecodes kershawi Perkins, 1921 = S. javanensis Blüthgen, 1927, syn. nov.; S. simlaensis Blüthgen, 1924 = S. simlaellus Blüthgen, 1927, syn. nov.; S. laticeps Meyer, 1920 = S. biroi mariae Cockerell, 1930, syn. nov. Lectotypes are designated for Sphecodes biroi Friese, 1909, S. simlaellus Blüthgen, 1927, and S. laticeps Meyer, 1920. The female of Sphecodes sauteri Meyer, 1925, and the male of S. turneri Cockerell, 1916 are described for the first time.


Introduction
In recent years significant progress has been made towards a better knowledge of the species of Sphecodes Latreille from central and northern Asia (Astafurova and Proshchalykin 2014, 2015a, b, c, 2017a, b, 2018Astafurova et al. 2015Astafurova et al. , 2018aAstafurova et al. , b, c, d, 2019. The purpose of this review is to improve our knowledge of the taxonomy and distribution of Sphecodes in Southeast Asia (Fig. 1) as an essential foundation for advancing biogeographical investigations in the Oriental Region.
Southeast Asia is composed of eleven countries of impressive diversity in habitats and landscapes: Brunei, Myanmar (Burma), Cambodia, East Timor, Indonesia, Laos, Malaysia, the Philippines, Singapore, Thailand and Vietnam (Fig. 1). This region has one of the highest concentrations of endemic species on Earth (Myers et al. 2000;Sloan et al. 2014;Sing et al. 2016) but knowledge of its bee fauna other than the relatively well-studied highly eusocial hive bees (Apini and Meliponini) remains very limited and inaccessible (Ascher et al. 2016). Currently 975 Southeast Asian species of Halictidae from fifteen genera are recognized as valid (Ascher and Pickering 2019), but the taxonomy and distribution of these species requires much additional study. We begin here with reference to the genus Sphecodes Latreille.
The first information on the genus Sphecodes from Southeast Asia was published by Bingham (1897), who record S. apicatus Smith [= S. gibbus (Linnaeus)] from the Pegu Hills, Burma (= Myanmar). But it is obvious that this is a misidentification and the record actually refers to another large Sphecodes species. Sphecodes brunneipes Friese, 1914 was the first species of the genus Sphecodes described from Southeast Asia (Indonesia) and since then eleven additional species have been described from this area by Cockerell 1915Cockerell , 1919Cockerell , 1930, Blüthgen 1924Blüthgen , 1927, and Meyer 1925 (three species), with only seven of them still valid (current data). Until now there has been no review published on Southeast Asian Sphecodes and all information on the distribution of the 17 known species was only available on the Discover Life website (Ascher and Pickering 2019).
In the present paper, based on a comprehensive study of specimens (including primary types) held in various collections, we report additional records of 21 species, with four species described as new and nine species recorded from Southeast Asia for the first time, resulting in a total number of 31 Sphecodes species known from this region ( Table 1). The genus Sphecodes has not yet been docu mented from Brunei, Cambodia, and East Timor although it is probable that this cosmopolitan genus is present in these countries and it is only a matter of time before the fauna is sampled and recorded.
Specimens were studied with a Leica M205A stereomicroscope and photographs tak en with a combination of stereomicroscope (Olympus SZX10) and digital camera (Olympus OM-D and Can on EOS70D). Final images are stacked composites using Helicon Focus 6. All images were post-processed for contrast and brightness using Adobe Photoshop.
New distributional records are noted with an asterisk (*).
above the antennal sockets) with adpressed white pubescence obscuring integument. Mesoscutum  Diagnosis. The female of this species resembles Sphecodes takaensis Blüthgen, 1927 owing to a similar structure, sculpture and coloration of the body, but it differs from this species by the square F3 (as long as wide), the entirely areolate vertex and the wider pygidial plate which is as wide as metabasitarsus (in S. takaensis F3 0.7-0.8 times as long as wide; vertex with small shiny impunctate spots near ocelli; pygidial plate narrower than metabasitarsus). Descriptive notes. Wings with brownish darkening; hind wing with the angle between basal (M) and cubital (Cu) veins ca. 80°, costal margin with eight or nine hamuli. Lateral preoccipital carina present. Female. Total body length 8-9 mm. Head ( Fig. 8) transverse, ca. 1.25 times as wide as long; vertex weakly elevated with distance from top of head to upper margin of lateral ocellus approximately a lateral ocellar diameter as seen in frontal view; labrum trapezoidal, 0.45 times as long as basal width; face and vertex areolate-punctate; paraocular (below and above the antennal sockets), supraclypeal areas and gena with adpressed white pubescence obscuring integument. Mesoscutum and mesoscutellum (Fig. 10) densely punctate (40-75 μm), medially with punctures separated by at most 1-2 puncture diameters, becoming confluent peripherally; propodeal triangle (metapostnotum) and mesepisternum ( Fig. 9) reticulate-rugose. Metasoma red (Fig. 11); T1 on disc and marginal zone finely and densely punctate (10-15 μm / 0.5-3), remaining terga more coarsely punctate (10-25 μm) with impunctate and smooth marginal zones; pygidial plate dull, widely rounded apically, as wide as metabasitarsus. Male unknown.
Diagnosis. Unlike other species with simple mandibles in the female, this species has a preoccipital carina and a weakly curved basal vein in hind wing. Descriptive notes. Wings with brownish darkening; hind wing with the angle between basal (M) and cubital (Cu) veins ca. 70°, costal margin with seven hamuli. Lateral and dorsal preoccipital carina present. Female. Total body length 6-7 mm. Head ( Fig. 23) strongly transverse, ca. 1.25 times as wide as long; vertex weakly elevated with distance from top of head to upper margin of lateral ocellus approximately a lateral ocellar diameter as seen in frontal view; F1 and F2 strongly transverse, 0.5 times as long as wide; F3 0.8 times as long as wide; face with confluent punctures, ocello-ocular area with dense punctures separated by at most a puncture diameter (Fig. 22); paraocular and supraclypeal areas with adpressed white pubescence obscuring integument. Gena with dense pubescence. Mesoscutum and mesoscutellum (Fig. 25) coarsely and densely punctate (25-50 μm), the punctures separated by at most two puncture diameters; mesepisternum reticulate-rugose (Fig. 24); propodeal triangle (metapostnotum) coarsely reticulate-rugose, lateral parts of propodeum with fine wrinkles (strigose). Metasomal terga definitely punctate (Fig. 26), finely on T1 (ca. 10 μm) and more coarsely on the remaining terga (10-25 μm); marginal zones impunctate; T1 and T2 red, coloration of T3 and T4 variable; pygidial plate dull, widely rounded apically, 1.4 times as wide as metabasitarsus. Male unknown.  Diagnosis. This species resembles Sphecodes shillongensis Blüthgen, 1927 andS. simlaensis Blüthgen, 1924, sharing a similar structure and sculpture of the body, including weakly developed antennal tyloids, a densely punctate mesoscutum and scarcely punctate metasomal terga. The species differs from S. simlaensis in having dense facial pubescence obscuring integument above the antennal sockets; from S. shillongensis it differs by shorter antennae with flagellomeres (from F3 onward) ca. 1.1-1.2 times as long as wide (versus 1.3) and shape of the gonostylus with a large membranous part. Distribution. *Laos, India (Bihar).  Diagnosis. Among the oriental species lacking a preoccipital carina and with five or six hamuli in hind wing the male of the new species is recognizable by having tyloids covering the entire ventral and lateral flagellar surfaces and also in the shape of the gonostylus which has an elongate membranous part; the female is similar to Sphecodes tantalus Nurse, 1903 by combination of the strongly transverse head, the metafemur strongly enlarged in proximal half, the mesoscutum with relatively sparse punctures, the impunctate T1, the narrow pygidial plate and the reddish metasoma, but it differs by not having an elevated vertex as seen in frontal view (in S. tantalus distance from top of head to upper margin of lateral ocellus approximately a lateral ocellar diameter).
Male. Total body length 6-7 mm (Fig. 34), fore wing 4.5-5.0 mm. Head black (Fig. 36), transverse, ca. 1.2 times as wide as long; vertex not elevated as seen in frontal view and distance from top of head to upper margin of a lateral ocellus approximately two lateral ocellar diameters as seen in dorsal view; antenna short ( Fig. 37), reaching posterior half of mesoscutum, F1 0.6 times as long as wide, F2 1.3-1.4 times as long as wide, remaining flagellomeres 1.1-1.2 times as long as wide; tyloids covering entire ventral and lateral flagellar surfaces; face densely punctate, the punctures separated by at most a half puncture diameter; ocello-ocular area and gena more sparsely punctate with punctures separated by approximately a puncture diameter; face and gena with sparser pubescence, not obscuring integument. Mesosoma black, tibia (partially) and tarsi yellow; mesoscutum ( Fig. 39) irregularly punctate, with confluent punctures peripherally and sparser medially (15-25 μm / 1-4); mesoscutellum coarsely punctate (20-40 μm) with punctures separated by at most a puncture diameter; hypoepimeral area and mesepisternum reticulate-rugose; propodeal triangle with coarse longitudinal wrinkles and shiny interspaces; lateral part of propodeum coarsely reticulate-rugose. Metasoma dark brownish (Fig. 38); terga almost impunctate with a few minute punc- Etymology. This species is dedicated to name of the website https://www.discoverlife.org (creators are J.S. Ascher and J. Pickering), in recognition of its contribution to knowledge of bee biodiversity.

Diagnosis.
Structurally and sculpturally this species is extremely similar to the female of Sphecodes bakeri Cockerell, 1915, but it differs in the ocello-ocular area (Fig. 4 having shiny interspaces and T2 basally possessing fine and sparse punctures (versus ocello-ocular area with entirely confluent punctures without interspaces (Fig. 5) and T2 impunctate in S. bakeri).
Descriptive notes. Wings with yellow-brownish darkening; hind wing with angle between basal (M) and cubital (Cu) veins almost 90°, costal margin with eight hamuli. Lateral preoccipital carina present. Female. Total body length 5-6 mm. Head strongly transverse (Fig. 2), ca. 1.35 times as wide as long; vertex weakly elevated with distance from top of head to upper margin of lateral ocellus approximately a lateral ocellar diameter as seen in frontal view; labrum trapezoidal, 0.6 times as long as basal width; face and ocello-ocular area with dense punctures separated by at most a half puncture diameter; paraocular and supraclypeal areas with adpressed white pubescence obscuring integument, gena with sparser pubescence. Mesoscutum and mesoscutellum (Fig. 6) areolate-punctate (30-50 μm); propodeal triangle (metapostnotum) with longitudinal wrinkles and deep large shining interspaces between them; lateral parts of propodeum with parallel wrinkles and large shining interspaces; mesepisternum reticulate-rugose. Metasomal terga red, almost impunctate (Fig. 7 Diagnosis. As with members of the Palaearctic hyalinatus species group (Astafurova and Proshchalykin 2017a), the new species has a pronotum rounded between the dorsal and lateral surfaces, but it differs in the strongly transverse head (1.3 times as wide as long) with a straight upper margin as seen in frontal view (versus head 1.2-1.25 times as wide as long with rounded vertex as seen in frontal view in species of the hyalinatus group).
Male unknown.
Etymology. This species is dedicated to our colleague Dr. Michael S. Engel (University of Kansas, USA), in recognition of his significant contributions to systematic entomology.
Distribution. Laos, Vietnam. Diagnosis. The male of this species resembles Sphecodes assamensis Blüthgen, 1927 in having a similar size of antennal tyloids and shape of the gonostylus, but it differs from this species by shining interspaces on vertex and mesoscutum (dull in S. assamensis), and the number of hamuli (ten or twelve versus eight). The female differs from other oriental species by combination of the following characters; lack of a preoccipital carina, large body length (9.5-12 mm), eleven or twelve hamuli, mesoscutum mostly punctate-areolate and vertex strongly elevated. With these characteristics the female is similar to the palaearctic S. albilabris (Fabricius, 1793), but it differs in a sparsely punctate T1 disc with punctures separated by 2-6 puncture diameters (versus 0.5-2 in S. albilabris). Descriptive notes. Wings with strong brownish darkening; hind wing with the angle between basal (M) and cubital (Cu) veins ca. 70°, costal margin with eleven or twelve hamuli. Female. Total body length 9.5-12 mm. Head (Fig. 60) transverse, 1.25 times as wide as long; vertex strongly elevated with distance from top of head to upper margin of lateral ocellus ca. two lateral ocellar diameters as seen in frontal view; supraclypeal area swollen; labrum short, semi-oval, 0.45 times as long as basal width; ocello-ocular area areolate-punctate, but vertex behind ocelli with shiny interspaces; paraocular areas and gena with relatively dense plumose pubescence although not obscuring integument. Mesoscutum and mesoscutellum (Fig. 62) mostly with confluent punctures (50-75 μm), but medially with a few interspaces at most 1-2 puncture diameters; propodeal triangle (metapostnotum) coarsely reticulate-rugose; mesepisternum ( Fig. 61) areolate on an upper half to reticulate below. Metasoma (Fig. 63) red; T1 sparsely punctate (ca. 25 μm / 2-6), finer and denser on marginal zone; remaining terga more densely and coarsely punctate, but marginal zones impunctate; pygidial plate dull, 1.3-1.4 as wide as metabasitarsus. Male. Total body length 9.5-12 mm. Head (Fig. 64) transverse, 1.2 times as wide as long; vertex strongly elevated with the distance from top of head to upper margin of lateral ocellus more than two lateral ocellar diameters as seen in frontal view; antenna (Fig. 66) long, reaching mesoscutellum, F2 1.8 times as long as wide, remaining flagellomeres ca. 1.4-1.5 times as long as wide; tyloids weakly developed, narrowly semicircular across basal 1/8-1/7 of flagellar surfaces and narrowly linear across remainder of flagellomere as seen in lateral view. Mesoscutum and mesoscutellum (Fig. 67) mostly areolate-punctate, but medially with a few interspaces approximately a puncture diameter wide; propodeum and mesepisternum as in the female. Metasoma (Fig. 68)  Diagnosis. This species is most close to Sphecodes kershawi and also resembles S. formosanus Cockerell, 1911, S. takaensis Blüthgen, 1927, and S. binghami owing to similar structure, sculpture, and coloration of the body, including a densely punctate disc and marginal zone of T1 (differences between females of these species are outlined in Table 2). Structurally and sculpturally the species is also close to S. distinctus and S. sibuyanensis Cockerell, 1925 and one of these species may possibly be the unknown male of S. howardi, especially S. sibuyanensis which has the same brown wing coloration (lighter and yellowish in S. distinctus). Descriptive notes. Wings with brownish darkening; hind wing with angle between basal (M) and cubital (Cu) veins ca. 70°, costal margin with seven or eight hamuli. Lateral preoccipital carina present. Female. Total body length 8.5-9.5 mm. Head transverse, ca. 1.25 times as wide as long; vertex elevated with distance from top of head to upper margin of lateral ocellus approximately a lateral ocellar diameter as seen in frontal view; labrum semi-oval, 0.4 times as long as basal width; face and vertex areolate-punctate; paraocular (below and above the antennal sockets), supraclypeal areas and gena with adpressed white pubescence obscuring integument. Mesoscutum and mesoscutellum mostly with areolate punctures (40-75 μm), but medially with a few shining interspaces of approximately a puncture diameter (Fig. 69); propodeal triangle (metapostnotum) reticulate-rugose (sculpture forming Description. Wings with weak yellow-brownish darkening, veins and stigma brown; hind wing with the angle between basal (M) and cubital (Cu) veins ca. 70°, costal margin with seven or eight hamuli. Lateral preoccipital carina well developed. Male. (holotype, Fig. 75). Total body length 8.5-9.0 mm, fore wing 5.6-5.7 mm. Head black (Fig. 76); weakly transverse, ca. 1.15 times as wide as long; vertex elevated, distance from top of head to upper margin of a lateral ocellus ca. one and a half of lateral ocellar diameter as seen in frontal view and ca. two as seen in dorsal view; antenna short (Fig. 77), reaching posterior half of mesoscutum; F1 strongly transverse, 0.4 times as long as wide; remaining flagellomeres 1.2-1.3 times as long as wide; tyloids semi-oval across at most basal 1/2 of last flagellomeres; supraclypeal area weakly bulging; clypeus shining, densely punctate with the punctures (20-30 μm) separated by at most a half puncture diameter. Supraclypeal and paraocular areas dull, finely areolate-punctate (15-25 μm), but frons and vertex close to reticulate-rugose; gena shining, rugose with sparse short setae; paraocular and supraclypeal areas with dense plumose adpressed pubescence. Mesosoma black (Fig. 78); mesoscutum coarsely areolate-punctate (50-75 μm), medially closer to reticulate-rugose; mesoscutellum densely and coarsely punctate, medially with the punctures separated by at most a puncture diameter; hypoepimeral area reticulate rugose; mesepisternum and propodeal triangle (metapostnotum) roughly reticulate-rugose; mesepisternum with sparse and thin short setae; lateral parts of propodeum shining, close to striate. Metasoma (Fig. 80) distinctly punctate, T1 with minute (5-15 μm) numerous punctures; remaining terga coarsely punctate (15-25 μm / 0.5-2); marginal areas impunctate except on T1 which has fine and sparse punctures basally; sterna tessellate with shallow setae pores; gonocoxite dorsally without impression; gonostylus with triangular apical process (Fig. 79); T1-T3 and S1-S3 variable in coloration, partially red, remaining terga and sterna brownish.
Female unknown. Etymology. The species is named after the author's daughter Darya Gayday and her husband Ilya Gayday, who recently married. It is to be treated as a noun.
Distribution. Indonesia. Diagnosis. The male of this species is closest to Sphecodes sibuyanensis Cockerell, 1925 owing to similar short antennae with tyloids covering the entire ventral flagellar surface, a densely punctate metasoma (including marginal zone on T1) and in the shape of the gonostylus, with an elongate membranous part. From S. sibuyanensis it differs by a mostly punctate-areolate mesoscutum (versus a lot of mesoscutellar punctures separated by 0.5-1 puncture diameter). The female is closest to S. howardi and is also similar to S. formosanus, S. takaensis, and S. binghami owing to a similar structure, sculpture and coloration of the body, including the densely punctate disc and marginal zone of T1 (differences between females of these species are outlined in Table 2). Descriptive notes. Wings with strong brownish darkening; hind wing with the angle between basal (M) and cubital (Cu) veins ca. 70°, costal margin with six, seven or eight hamuli. Lateral preoccipital carina present. Female. Total body length 7.5-8 mm. Head transverse (Fig. 73), ca. 1.2 times as wide as long; vertex elevated with distance from top of head to upper margin of lateral ocellus approximately a lateral ocellar diameter as seen in frontal view; labrum semi-oval, 0.5 times as long as basal width; face and vertex areolate-punctate; paraocular areas with dense adpressed white pubescence, gena with sparser pubescence not obscuring integument. Mesoscutum (Fig. 70) mostly areolate-punctate (50-75 μm) medially with a few punctures separated by at most 0.5-1 puncture diameter; mesoscutellum with confluent punctures and a few interspaces of approximately a puncture diameter. Propodeal triangle (metapostnotum) reticulate-rugose. Metasoma densely punctate (Fig. 74); T1 on disc and marginal zone finely punctate (10-15 μm / 0.5-3), remaining terga coarsely punctate (10-25 μm) with impunctate and smooth marginal zones, sometimes finely tessellate on T4 (Fig. 72); pygidial plate 0.7 times as wide as metabasitarsus; T1-T3 red. Male. Total body length 7-8 mm. Head transverse (Fig. 81), ca. 1.2 times as wide as long; vertex elevated with distance from top of head to upper margin of lateral ocellus approximately a lateral ocellar diameter as seen in frontal view; antennae short ( Fig. 82), not reaching mesoscutellum, F1 0.6 times as long as wide, remaining flagellomeres ca. 1.2 times as long as wide, tyloids covering entire ventral flagellar surface. Mesosomal sculpture as in female (Fig. 84). Metasomal T1 densely punctate including marginal zone (10-20 μm / 0.5-2), remaining terga with impunctate marginal zones (Fig. 83); T1-T3 red or metasoma entirely black; gonocoxite dorsally without impression; gonostylus with elongate membranous part, apically with long setae (Fig. 85).  Perkins Coll., B.M. 1942-95 (NHMUK 013380470).
Male unknown. Etymology. The species name highlights the morphological similarity with S. redivivus Blüthgen.

Sphecodes samarensis
Diagnosis. This species is closest to Sphecodes bakeri (refer to diagnosis of S. bakeri, above). The male is also similar to S. biroi Friese, 1909 andS. laticeps Meyer, 1920 owing to a similar structure, sculpture and coloration of the body, including the shape of the male genitalia. The species differs from S. laticeps by the areolate and less elevated vertex with distance from top of head to upper margin of lateral ocellus half or one of a lateral ocellar diameter as seen in frontal view (versus shining vertex with interspaces between punctures and distance from top of head to upper margin of lateral ocellus one and a half or two lateral ocellar diameters. The female of S. samarensis is unknown, but these features would work in both sexes). From S. biroi the species differs in the shape of tyloids with a glabrous medial spot on ventral surface of flagellomeres (versus tyloids usually covering entire ventral flagellar surface or sometimes with a small non-setae spot on basal flagellomeres). The unknown female is probably closest to S. duplex and S. bakeri. Descriptive notes. Wings with weak yellow-brownish darkening; hind wing with the angle between basal (M) and cubital (Cu) veins almost 80°, costal margin with seven hamuli. Lateral preoccipital carina present. Male. Total body length 5-6.5 mm. Head (Fig. 110) transverse, ca. 1.25 times as wide as long; vertex weakly elevated with the distance from top of head to upper margin of a lateral ocellus half or one of a lateral ocellar diameter as seen in frontal view; antennae (Fig. 110) short, reaching posterior margin of mesoscutum, F2 ca. 1.5 times as long as wide, remaining flagellomeres ca. 1.2 times as long as wide; tyloids well developed, covering entire lateral flagellar surfaces and peripheral part of ventral surface (ventral surface medially with glabrous round spot); face and vertex (Fig. 111) finely areolate-punctate; face (below and above the antennal sockets) with adpressed white pubescence obscuring integument, gena with sparser pubescence. Mesoscutum and mesoscutellum areolate (Fig. 112); propodeal triangle sculpture roughly reticulate-rugose, forming a row of large deep longitudinal cells; lateral parts of propodeum rugose with large smooth shiny interspaces. Metasomal terga (Fig. 113) with fine punctures (10-15 μm /1-3); marginal zones impunctate; T1-T3 red; gonocoxite dorsally without impression; gonostylus as on Fig. 114.  Meyer, 1925 Figures 115-126 Sphecodes sauteri Meyer, 1925: 10, ♂ (holotype: ♂, "Formosa [Taiwan], Mt. Hoozan, 1910"; HNHM, examined, Fig. 125).

Remarks.
It is noteworthy that the other cleptoparasitic genus Nomada Scopoli (Apidae) also has a small group of species with two submarginal cells (Proshchalykin and Lelej 2010).

Discussion
The most important figures, on which the study is based, are shown in Table 1, which assigns the individual species to the countries of Southeast Asia, with the respective totals and number of collection points. Amongst all bees in the collections we studied, the proportion of specimens from the Oriental Region belonging to the genus Sphecodes present turned out to be scanty, which suggests that the genus in this region is extremely rare. Although the number of species recorded here (approximately 50) is less than in the Palaearctic Region (approximately 70), this number will probably exceed the number of Palaearctic species eventually as further new species are described. In total, 31 species of Sphecodes are recorded from Southeast Asia (Table 1) and only eleven of these have a distribution beyond the studied region (India, Pakistan, China). However, the record of 20 other species confined to Southeast Asia does not indicate a large degree of endemicity of the fauna, but rather suggests an incomplete knowledge of the distribution of the oriental fauna of Sphecodes.
Most species recorded in Southeast Asia have montane distributions and are found up to 1900 m. The range of S. biroi, which is distributed from New Guinea to India, is the widest among Southeast Asian species. Sphecodes simlaensis, S. montanus, S. sikkimensis, and S. fumipennis are also probably widespread in the mountainous areas of the Oriental Region.
Morphologically, a large proportion of Southeast Asian species have close affinities to some of the Palaearctic species or belong to one of the Palaearctic species groups. Sphecodes engeli belongs to the hyalinatus species group (for the composition of Palaearctic species groups see Astafurova and Proshchalykin 2017a); S. discoverlifei is similar to S. crassus Thomson, 1870;S. montanus