Review of the odd chrysidid genus Loboscelidia Westwood, 1874 (Hymenoptera, Chrysididae, Loboscelidiinae)

Abstract The chrysidid genus Loboscelidia is reviewed and 11 new species are described, including Loboscelidia cinnamonea (Borneo), Loboscelidia fulgens (Viet Nam), Loboscelidia fulva (Thailand), Loboscelidia incompleta (India), Loboscelidia kafae (Borneo), Loboscelidia laminata (Viet Nam), Loboscelidia meifungae (Borneo), Loboscelidia nasiformis (Thailand), Loboscelidia nitidula (Thailand), Loboscelidia pecki (Viet Nam), and Loboscelidia sisik (Borneo). A key to males of the species of Loboscelidia is given.


Introduction
Loboscelidiinae is one of the smaller subfamilies in the family Chrysididae. The subfamily contains two genera, Loboscelidia Westwood, 1874 and Rhadinoscelidia Kimsey, 1988. As of the publication of Kimsey and Bohart (1991), Loboscelidia contained 30 species and Rhadinoscelidia one species. Since then four Loboscelidia and two Rhadinoscelidia species have been added (Kojima and Ubaidillah 2003, Terayama et al. 1998, Xu et al. 2006). An additional 11 new Loboscelidia species are described below. This study focuses on males and their characteristics as the systematics of the group is focused primarily on this sex due to the rareness of females in collections and the strong sexual dimorphism between males and females.
The subfamily is primarily south Asian with four northern Australian species. Every major south Asian island may have at least one endemic species of Loboscelidia, and every new intensive collecting effort using Malaise traps or flight-intercept traps turns up new species. Thus, the loboscelidiine fauna appears to be largely under-sampled.
Loboscelidiines are among the most aberrant-looking and highly modified chrysidids, and as a result their actual family and even superfamily placement has varied considerably over the years. These are small-bodied, non-metallic brown wasps, with a superficial resemblance to members of the family Diapriidae (see Fig. 1). In fact Westwood (1874) originally described Loboscelidia as a species of diapriid (Superfamily Proctotrupoidea). Ashmead (1902) then moved the genus to the family Figitidae (Superfamily Cynipoidea). Maa and Yoshimoto (1961) then moved the genus Loboscelidia into its own family, Loboscelidiidae (Superfamily Bethyloidea). Finally, after making a detailed analysis of the metasomal morphology Day (1978) concluded that the group actually belonged in the family Chrysididae (Superfamily Chrysidoidea).
Loboscelidiines are characterized by a number of unusual features (Figs 1, 2). The antennae insert horizontally on a shelf-like extension in the middle of the face (the shelf-like extension is termed the frontal projection below); the vertex is prolonged posteriorly into a neck-like projection fringed with ribbon-like setae; the pronotum is not freely hinged to the scutum and has a short line of ribbon-like setae along the anterolateral corner; the tegula is very large, covering both wing bases, and is held in place by a ridge on the mesopleuron; the mesopleuron is smooth without sculpturing, except for a shallow, trough-like scrobal sulcus in some species, the propodeum lacks a dorsal surface and has an ear-like lateral projection over the spiracle, and the forewing lacks a stigma, costal and subcostal veins.
Distinctions between Loboscelidia and Rhadinoscelidia have been summarized in Kimsey and Bohart (1991). Briefly Loboscelidia can be distinguished from Rhadinoscelidia by the forewing venation extending into the basal one-third to one half of the wing (considerably less than one-fourth in Rhadinoscelidia), vertex convex or flat behind the ocelli, not sharply declivitous as in Rhadinoscelidia, and cervical expansion continuous with head, without discrete posterior expansion and with well-developed genal and cervical fringe. Cervical expansion basally constricted and shield-like posteriorly, with small discontinuous genal and cervical fringes in Rhadinoscelidia.
Members of the genus Loboscelidia are strongly sexually dimorphic, which has led to confusion over generic placement and sex associations. The genus Scelidoloba Maa & Yoshimoto, 1961 was erected for what turned out to be female Loboscelidia (Day 1978). Males have five external metasomal segments and a long slender flagellum. Females are heavier bodied than the males, with a shorter, broader flagellum and an externally foursegmented metasoma. It's not clear how many characteristics are shared between the two sexes as fewer than 15% of specimens in collections are female and more than one species may be present in a single locality. However, the sexes do seem to share some modifications of the wing venation (presence and shape, or absence of the medial vein), shape of the frontal projection, and presence or absence of the scrobal sulcus and notauli.
Little is known of the biology of the Loboscelidiinae. Specimens are rare in collections. However, this situation is probably more a reflection of collecting techniques used and sites visited than any indication of abundance. Malaise trapping in Thailand as part of the National Science Foundation funded TIGER project has yielded more than 100 Loboscelidia specimens, more than all other museum holdings. The small number of female Loboscelidia collected relative to males may be due to their differing habits. Males may be more frequently caught in traps because they tend to frequent low vegetation and the surface of leaf litter searching for females. Females may spend most of their time in cryptic situations, for example under bark or in the leaf litter, searching for hosts.
The morphology of the female ovipositor and mandibles closely resembles that of the Amiseginae, suggesting that loboscelidiines, like amisegines parasitize walking stick eggs. There is one report of an unidentified species of Loboscelidia reared from the eggs of the phasmatid Acrophylla sp. (Riek 1970). It is also possible, given the structural modifications of the group, including the leg and antennal flanges, the very large tegula and the tegular clip that Loboscelidia females at least may search for walking stick eggs in ant nests. Fouts (1922) suggested that the group is myrmecophilous based on the odd morphology. Walking stick eggs may be collected by ants because of the egg's strong resemblance to seeds.

Materials and methods
China Agricultural University, Guangzhou, and ZFCL -Hymenoptera Collection, Zhejiang University, Hangzhou, China.
Morphological terminology follows that used by Kimsey and Bohart (1991) and is further described in Fig. 2. The hindwing lacks venation, so wing vein characters are only for the forewing. Wing veins are given in the text as abbreviations: Cu = cubital vein, cu-a = cubital-anal cross vein, M = medial vein, R = radial vein, Rs = radial sector, R1 = first radial branch. Scrobal sulcus refers to the transverse trough on the mesopleuron below the forewing ending in the scrobe adjacent to the metapleuron. The shape of the frontal projection is determined viewed in front view. It is considered triangular if the ventral angle of the projection ends in a point or the flat surface is less than one-tenth the length of the upper surface. The projection is considered rectangular if it is a true rectangle or rhomboid. Head length versus width is measured from the apex of the cervical extension to the furthermost point of the frontal projection and across the widest part of the head in lateral view. Antennal articles are measured at the point of greatest breadth and compared with the total length of the article. Wing veins are compared relative to the length of R1. Pronotal dimensions are measured from the medial length of the pronotum in dorsal view to the distance between the apices of the posterolateral angles. The length of a leg flange is measured from the basal joint to the apex of the segment along the ventral margin. The relative width of leg flanges are measured across the broadest part of the flange relative to the tubular part of the segment at the same point.  Gena and often legs with scattered scale-like setae (as in Fig. 16 Scrobal sulcus present at least as a series of pits or foveae (as in Fig. 2); scape 3.0× as long as broad or shorter; cu-a 0.3× as long or longer than R (as in Fig. 27) ...16 -Scrobal sulcus absent; scape 3.5× as long or longer as broad; cu-a absent ... 17 16

Key to males of the species of Loboscelidia
Face frontal projection rhomboid or rectangular in front view; Rs 3.0× as long as R (Fig. 27); midtibial flange more than half as long and wide as tubular part of tibia (Fig. 39) Frontal projection triangular (as in Fig. 19 Foretibial flange narrower than tubular part of tibia (as in Fig. 40) ...........39 -Foretibial flange as wide or wider than tubular part of tibia (as in Fig. 41 Material studied. Singapore (USNM); Indonesia: West Kalimantan, Gunung Palung National Park (1 female, ROM); 2 female specimens were examined including the holotype. Diagnosis. The male of this species is unknown, but antennata may very well prove to be the female of brunnea Fouts, based on the triangular frontal projection, flattened cervical expansion, curved medial vein and lack of a scrobal sulcus.
Material studied. Only the holotype was seen.
Diagnosis. The most distinctive feature of Loboscelidia asiana is the presence of spatulate or leaf-like setae on the gena, a character shared only with sisik (as in fig. 16). However, asiana can be distinguished from sisik by the submedially curved medial vein (nearly flat in sisik), scape striate and more than 3.5× as long as broad (smooth and less than 3× as long as broad in sisik) and no scrobal sulcus (present in sisik).

Material studied.
Only the holotype was seen.
Diagnosis. This is one of several species with a well-developed, complete scrobal sulcus. A combination of features will separate atra from these other species, including the rectangular frontal projection (in lateral view), scape more than 3× as long as broad, cu-a vein less than half as long as R, Rs twice as long as R, and metanotum half as long as the scutellum.  Material studied. Australia: New South Wales, Queensland; two specimens were seen including the holotype.

Loboscelidia australis
Diagnosis. This is one of three species (including maculata and ora), all Australian, that lack notauli (as in Fig. 22). L. australis can be distinguished from these by the submedially curved medial vein, rectangular frontal projection, pronotum with sharp lateral fold or ridge, flagellomere XI less than 3× as long as broad, and fore and midtibial flanges less than 0.5× as long as their respective tibial lengths.
Material studied. Malaysian Borneo, Sabah, Sandakan (2 males, USNM), Kinabalu National Park Poring Hot Springs (2 males including two syntypes, CNC, USNM). Diagnosis. Loboscelidia bakeri can be immediately distinguished from all other Loboscelidia species by the distinctively dorsomedially up-domed propodeum. It is also one of four species, including fulgens, reducta and ganxiensis that lack a medial vein (as in Fig. 24). Diagnosis. This is one of the species with a complete scrobal sulcus and triangular frontal projection. It shares a long scape (more than 3× as long as broad) with one of these, laotiana. L. castanea can be distinguished from these species and laotiana by a combination of characters, including cu-a less than 0.5× as long as R, A 0.6× as long as Cu+M, flagellomere I shorter than II, flagellomere XI more than 4× as long as broad, and the fore, mid and hindfemoral flanges as broad as the tubular part of the respective femora.
Material studied. New Britain: near Keravat only the holotype was seen.
Diagnosis. This is one of two species, including parva, known from New Britain. Both have the notauli not reaching the posterior margin of the scutum (Fig. 23) and the frontal projection sublinear in front view. L. cervix can be distinguished from parva by the shorter scape (2.6-2.8× as long as broad in cervix, 3.0-3.1× in parva), Rs more than 3× as long as R (less than 3× in parva), cu-a longer than R (shorter in parva) and partial scrobal sulcus (absent in parva). The Australian species ora is the only other Loboscelidia with long cu-a longer than R. Additional non-type specimens (27)  Diagnosis. L. cinnamonea is most similar to nasiformis, as both share an arched medial vein, rectangular frontal projection, complete notauli, without a scrobal sulcus and the cu-a vein reduced to a tiny stub or absent. It can be distinguished from nasiformis by the more typical frontal projection, fore and midtibiae without discrete, measureable flanges, R1 obsolescent and Rs 3× or more as long as R.
Etymology. The species name is Latin for brown as in the spice, cinnamon.
published as new species one month after the 1916a paper (1916b Diagnosis. This is one of four species, including bakeri, guangxiensis and reducta that completely lack a medial vein. L. fulgens can be separated from guangxiensis in males by the shorter Rs vein, 1.5× as long as R, versus twice as long in guangxiensis, and having well-developed tibial flanges, which are lacking in reducta. L. fulgens can be immediately distinguished from bakeri by lacking the uniquely up-domed propodeum characteristic of bakeri. Male description. Body length 1.5-2.0 mm; forewing length 2.0-2.5 mm. Head (Fig. 5): length 1.8× height in side view; eye asetose; frontal projection rectangular in front view; frons smooth, not microstriate; frons with low ridge extending from vertex along inner eye margin; vertex with transverse fovea, posterior expansion strongly curved in profile; gena without scale-like setae; scape striate, length 2.9× breadth; flagellomere I length 2× breadth; flagellomere II length 1.8× breadth; flagellomere XI length 3× breadth. Mesosoma: pronotal length 0.8× breadth, without lateral carina, narrower than head in dorsal view; scutum with notauli reaching posterior margin; scutellum with fine dense striae laterally; metanotum with medial ridge, impunctate laterally, 0.4× as long as scutellum; mesopleuron without scrobal sulcus; propodeum without transverse dorsal carina; legs (Fig. 38)

Diagnosis.
L. fulva is one of five species with a straight medial vein, including meifungae, maculata, ora and defecta. It can be distinguished from ora and maculata by having notauli, from defecta by having the cu-a vein one-half or more as long as R and Cu+M as long as A, and from meifungae by the rectangular frontal projection, Rs about 3× as long as R and the scutellum coarsely areolate (smooth to longitudinally striate in meifungae).
Male description. Body length 2.5 mm; forewing length 3.0 mm. Head (Fig.  6): length 1.6× height in side view; eye asetose; frontal projection rectangular in front view; frons with lateral ridge adjacent to eye margin; vertex without transverse fovea, posterior expansion strongly curved in profile; frons without carina or ridge extending from vertex along inner eye margin; gena without scale-like setae; scape smooth, length 2.7× breadth; flagellomere I length 1.6× breadth; flagellomere II length 1.7× breadth; flagellomere XI length 3.5-4.0× breadth. Mesosoma: pronotal length 0.8× breadth, with lateral carina, as wide as head in dorsal view; scutum with notauli reaching posterior margin; scutellum posteriorly coarsely rugose; metanotum with three medial ridges, impunctate laterally, 0.4× as long as scutellum; mesopleuron with scrobal sulcus; propodeum without transverse dorsal carina; legs (Fig. 39)  Diagnosis. This is one of five species, including incompleta, bakeri, reducta and fulgens, which have the medial vein partial or absent and cu-a less than 0.2× R or absent. It can be distinguished from these species by Rs more than twice as long as R and R1 more than 0.5× as long as R, flagellomeres I and II twice as long as broad, flagellomere XI less than 3× as long as broad and the hindtibial flange less than half as wide as the tubular part of the tibia.

Material studied. None
Diagnosis. This is another of the species with a flat medial vein. Loboscelidia halimunensis and defecta both lack a cu-a vein. The two species can be separated by the longer Rs vein in halimunensis (more than 2× as long as R, versus less than 2× in defecta) and pronotum as long as broad or broader (longer than broad in defecta). Despite contacting the authors the type could not be located.

Diagnosis.
The most distinctive and unique feature of this species is the medially incomplete medial vein. Among the species that lack a medial vein entirely, including bakeri, fulgens, reducta and guangxiensis, incompleta can be distinguished by the Rs vein twice as long as R (1.5× or less in the other species). It does share the fore and midtibial flanges lacking as in reducta.
Diagnosis. L. indica is one of two species described from India, including incompleta. It is also one of the dozen or so species with a scrobal sulcus and rectangular frontal projection. It can be distinguished from them by the combination of the Rs less than 3× as long as R, A as long or longer than Cu+M, scape less than 3× as long as broad, flagellomeres I and II twice or more as long as broad, and fore, mid and hindtibial flanges 1.5× or more as wide as the tibiae.

Material studied.
No reliably identified specimens have been seen. However, according to Kieffer's (1916) illustration inermis has a well-developed cu-a vein, unlike defecta, which lacks cu-a, or cu-a is represented by a very short stub. also found in pasohana and laminata. It can be distinguished from these two species by flagellomere XI 4× as long as broad (shorter in the other species), the fore and midtibial flanges as broad as the tibiae and the hindtibial flange twice as broad (narrower in various combinations in the other species).
Female. Unknown. Etymology. The species name refers to the coffee brown coloration (Thai for coffee, noun).
Diagnosis. L. laminata most closely resembles kafae as discussed under that species. However, laminata can be distinguished by flagellomere II less than twice as long as broad, flagellomere XI less than 3.5× as long as broad, and the fore and midtibial flanges narrower than the respective tibiae.
Male description. Body length 2.0-2.5 mm; forewing length 2.5-3.0 mm. Head (Fig. 10): length 1.8× height in side view; eye asetose; frontal projection rectangular in front view; frons with lateral ridge adjacent to eye margin; vertex without transverse fovea, posterior expansion shallowly curved in profile; frons with low ridge extending from vertex along inner eye margin; gena without scale-like setae; scape smooth, length 2.6× breadth; flagellomere I length 1.7× breadth; flagellomere II length 1.8× breadth; flagellomere XI length 4× breadth. Mesosoma: pronotal length 0.8× breadth, with/out lateral carina, nearly as wide as head in dorsal view; scutum with notauli reaching posterior margin; scutellum with fine dense striae; metanotum with three medial ridges, impunctate laterally; mesopleuron with scrobal sulcus; propodeum without transverse dorsal carina; legs (Fig. 41)   Material studied. Laos: Vientiane Prov, Ban Van Eue (2 males, BPBM, BME); Viet Nam: Fyan (1 male, BME); Malaysia: Sabah: Kinabalu Nat. Pk. (3 males, USNM); Indonesia: Sumatra, Aceh: Mt. Leuser Nat. Pk., Ketambe Res. Sta (1 male, ROM); 7 specimens were seen including the holotype. Diagnosis. L. laotiana is one of the species with a scrobal sulcus and a triangular frontal projection (Fig. 19). It can be distinguished from the others by the combination of the Rs 3× or more as long as R, scape striate and more than 3× as long as broad, flagellomeres I and II less than twice as long as broad, flagellomere XI less than 3× as long as broad, fore and midfemoral flanges as wide as the tubular part of the respective femora and the hindtibial flange twice as wide as the tubular part of the tibia.

Loboscelidia maculipennis
Diagnosis. This is one of four species with a strongly flattened cervical expansion (Fig. 11) as discussed under brunnea. L. maculipennis males can be distinguished from the other three by cu-a as long as R, Rs vein 4× or longer than R, leg integument smooth (Fig. 41), and hindtibial posterior margin with 2 parallel carinae.
Diagnosis. This species belongs in the group of species having a flat medial vein and notauli, including defecta and fulva. It can be distinguished from other members of the group by the triangular frontal projection, presence of a scrobal sulcus, cu-a present (shared with fulva) and midtibial flange absent.
Male description. Body length 2.0-4.0 mm; forewing length 2.5-4.5 mm. Head (Fig. 12): length 1.8-2.0× height in side view; eye asetose; frontal projection triangular in front view; frons smooth to microstriate; vertex without transverse fovea, posterior expansion strongly curved in profile; frons without discrete carina or ridge extending from vertex along inner eye margin; gena without scale-like setae; scape with some striae, length 2.1-2.5× breadth; flagellomeres I and II length twice breadth; flagellomere XI length 4× breadth. Mesosoma: pronotal length 0.7-0.8× breadth, with lateral carina; scutum with notauli reaching posterior margin; scutellum with sublateral carina, with fine dense striae laterally; scrobal sulcus represented by series of pits; metanotum with medial ridge, impunctate laterally; propodeum without transverse dorsal carina; legs (Fig. 42)  Diagnosis. The most distinctive and unusual feature of this species is the greatly elongate and nose-like frontal projection, which makes the head nearly 3× as long as broad in lateral view. Otherwise, nasiformis is closest to cinnamonea, with an arched medial vein, rectangular frontal projection (albeit greatly elongate in nasiformis), complete notauli, cu-a reduced to a tiny stub or absent, and no scrobal sulcus. Other than the elongate frontal projection, nasiformis can be separated from cinnamonea by the presence of fore and midtibial flanges (absent in cinnamonea).

Diagnosis.
As discussed under castanea and collaris, nigra is one of seven species with a triangular frontal projection, complete scrobal sulcus and complete notauli. Dimensions of the antennal articles will separate nigra from these species; the scape is less than 3× as long as broad, flagellomeres I and II are 2.5× as long as broad or longer and flagellomere XI is 4.5× as long as broad. Diagnosis. This is one of five species, including cervix, novoguineana, ora and parva, where the frontal projection is broadly flattened and nearly linear in front view. It can be distinguished from these species by the arched medial vein, cu-a as long as or longer than R, foretibial flange as wide as tubular part of tibia, and the mid and hindtibial flanges 1.5× as wide as tubular part of the tibiae or wider. Creek (1 male, BPBM); 6 specimens were seen including the otype series.

Loboscelidia nigricornis
Diagnosis. This is one of several species with a flat medial vein and rectangular frontal projection. In males, the absence of cu-a and the scape more than 3.3× as long as broad are characteristics nigricornis shares with halimunensis. L. defecta can be distinguished from halimunensis by Rs less than twice as long as broad (longer in halimunensis) and longer pronotum (1.2× as long as broad, versus as long as broad or broader in halimunensis).

Diagnosis.
L. ora can be distinguished from the other Loboscelidia species with an apically broad, flattened frontal projection (Fig. 18) by the nearly straight medial vein, cu-a longer than R, Rs more than twice as long as R, A as long or longer than Cu+M, and no notauli. Material studied. New Britain; only the holotype was seen.

Diagnosis.
As discussed under cervix and ora, parva is another of the species with a wide, broadly flattened frontal projection. L. parva can be distinguished from these species by the arched medial vein, scape 3× as long as broad, partial notauli, pronotum broader than long, and foretibia without a flange. Diagnosis. This a member of the large group of species with a rectangular frontal projection, submedially curved medial vein, complete scrobal sulcus and complete notauli. L. pasohana can be distinguished from the rest by the following combination of features: Rs nearly as long as R, cu-a half as long as R, flagellomeres I and II less than twice as long as broad, and fore, mid and hindtibial flanges 1.3-1.7× as wide as tubular part of respective tibiae.  Diagnosis. This species is characterized by the absence of the cu-a vein and having a submedially curved medial vein, characters shared with cinnamonea. It can be distinguished from cinnamonea by Rs 3× as long or longer than R, scape 3× or shorter as long as broad, scrobal sulcus present and the fore and midtibiae without flanges.
Etymology. The species is named after the collector, Stuart Peck.
Material studied. Philippines: Mindanao (3 males, USNM, BME); the 2 syntypes were also seen. Diagnosis. L. philippinensis is one of the group of species characterized by having a submedially curved medial vein, rectangular frontal projection, no scrobal sulcus, and cu-a vein present. It can be distinguished from the rest of the group by the short, broad head in side view (1.2-1.4× as long as high), flagellomere I is more than twice as long as broad and longer than flagellomere II, partial notauli, metanotum half as long or longer than scutellum, A shorter than Cu+M, and hindtibial flange as long as tibia and twice as wide as tubular part of tibia. Diagnosis. L. striolata may very well be part of the species group discussed under castanea and collaris, characterized by a triangular frontal projection, complete scrobal sulcus and complete notauli. However, the published description and images do not show the mesopleuron clearly enough to determine whether the scrobal sulcus is present or not. If it does have a scrobal sulcus then striolata may be synonymous with sinensis. Both striolata and sinensis share similar head, wing vein, flagellar and leg flange dimensions. They appear to differ in the dimensions of the scape, which 3× as long as broad in striolata and twice as long as broad in sinensis and possibly in the presence of the scrobal sulcus in sinensis.