A review of the Afrotropical Rhyssinae (Hymenoptera: Ichneumonidae) with the descriptions of five new species

Abstract. The Afrotropical Rhyssinae are reviewed. A total of 12 species are reported from the region, including five new species: Epirhyssa brianfisheri sp. nov., E. gavinbroadi sp. nov., E. shaka sp. nov., E. villemantae sp. nov. and E. tombeaodiba sp. nov. The generic status of E. brianfisheri sp. nov. is discussed since this species could also be considered to be an extra-limital Triancyra species, emphasizing the putative paraphyletic status of Epirhyssa. Epirhyssa ghesquierei Seyrig, 1937, E. overlaeti Seyrig, 1937 and E. uelensis Benoit, 1951 are newly reported from Cameroon. We provide illustrated diagnoses and identification notes. Finally, we discuss the apparent scarcity of African rhyssines compared to other regions.


Introduction
In many respects, Rhyssinae are atypical amongst Ichneumonidae. First, unlike most ichneumonids, they are rather well known to the public because of their spectacular habitus. The subfamily includes some of the largest species of ichneumonid wasps, exhibiting often striking color patterns. They also have very long ovipositors used to access their wood-boring hosts. For example, species of Megarhyssa Ashmead, 1900 often have an ovipositor that has a length of more than 20 cm, 3x longer than the entire body, i.e., relatively and absolutely some of the longest known in insects (Townes 1975). They are readily identifiable: the upper mandibular tooth is truncate and chisel-shaped, the mesoscutum is flattened and crossed by deep transverse rugosities, and the last tergite of the female bears an apical horn-like projection. Traditionally included as a tribe within Pimplinae, they were then considered as a separate monophyletic subfamily, mostly defined by the above autapomorphies, within the pimpliforme subfamily group (Gauld 1991;Wahl & Gauld 1998).
Second, their diversification history appears to be an exception to the general rule that most taxa in the tree of life arose in tropical areas and then diversified into the temperate areas (Jansson et al. 2013). The genus Rhyssa, considered to be the most basal lineage of Rhyssinae, is almost exclusively Holarctic, whereas the more derived genera are primarily or exclusively tropical; the origin of other pimpliform subfamilies (e.g., Diacritinae, Poemeniinae, Acaenitinae) was hypothesized to be in the Northern Hemisphere for similar reasons (Wahl & Gauld 1998). However, their actual diversity in the tropics, especially in the Neotropical and Afrotropical regions, appears to have been previously greatly underestimated (Quicke 2012;Veijalainen et al. 2013).
The generic composition of Rhyssinae in tropical and temperate regions may be correctly assessed by long-term sampling efforts. Rhyssinae are indeed exceptional for a third reason: due to their conspicuous habitus, their moderate diversity, and their potential economic impact for biocontrol of wood-boring pests, they received significantly more attention than most of the other ichneumonid subfamilies. Available reviews cover the following regions: Oriental and Australasian (Baltazar 1961;Kamath & Gupta 1972;Sheng & Sun 2010), Nearctic (Townes et al. 1960), Neotropical (Porter 1978;Gauld 1991;Gauld et al.1997), and Palaearctic (Horstmann 2002;Kasparyan & Khalaim 2007). They total about 250 species in eight genera (Yu et al. 2012). Nearly half of these species belong to the circumtropical genus Epirhyssa Cresson, 1865. All host records are coleopteran or symphytan larvae (Yu et al. 2012). They have also been reported to develop as facultative hyperparasitoids of other Symphyta parasitoids (Hanson 1939), and are able to oviposit and develop on many surrogate hosts (Spradbery 1968). Indeed, as idiobiont ectoparasitoids, the entire host selection process is only conditioned by what they can locate, led mostly by chemical and mechanical stimuli (Spradbery 1970): any potential host they eventually find is thus reduced to a mere "bag of meat" without any immune response to deal with, making the host range potentially broader.
In accordance with the general rule for Ichneumonidae, their diversity in the Afrotropical region has been poorly investigated. To date, only seven species have been reported from the region, of which six belong to Epirhyssa (Yu et al. 2012). This is a relatively poor richness in comparison with the 48 currently described Neotropical species (all Epirhyssa), to which many others have still to be added (Sääksjärvi et al. 2004), and the 140 Oriental and/or Australasian species (52 Epirhyssa). Rhyssinae are expected to be most species-rich in lowland tropical rainforests (Gauld 1991), and hence these seven Afrotropical species reflect the poor knowledge we have of the subfamily on this continent. This paper therefore aims firstly to review the currently known species, by gathering, translating and updating their descriptions (Seyrig 1937;Benoit 1951Benoit , 1952, secondly to add five new species from undetermined material housed in African and European museums, and then to provide proper identification and description tools for the expected numerous Rhyssinae species still to be collected in the Afrotropical Region. The scarcity of available specimens is discussed.

Photographs
Specimens were point mounted on black, acid-free card for examination (using a Leica M205C stereo microscope with a LED light source), photography and long-term preservation. Images were taken using the EntoVision® multiple-focus imaging system. This system combines a Leica® M16 microscope with a JVC® KY-75U 3-CCD digital video camera attached that feeds image data to a notebook computer. The program Cartograph®5.6.0 was then used to merge an image series (representing typically 10-15 focal planes) into a single in-focus image. Lighting was achieved using techniques summarized in Buffington et al. (2005), Kerr et al. (2008) and Buffington & Gates (2009

B
= body length, from toruli to metasomal apex (mm) A = antenna length, from base of scape to flagellar apex (mm) F = fore wing length, from tegula to wing apex (mm) CT = clypeus transversality index (maximum width of clypeus / median height) ML = malar line index (malar line / basal mandibular width) POL = post-ocellar index (shortest distance between posterior ocelli / ocellus maximal diameter) OOL = oculo-ocellar index (shortest distance between eye and posterior ocellus / ocellus maximum diameter) Fl n = length index of flagellomere n (length / width of flagellomere n) T1 = tergite 1 elongation index, (median length of tergite 1 / apical width (applies to female only if not otherwise specified)) OT = ovipositor sheath-tibia index (length of ovipositor sheath / length of hind tibia) The first three measurements (absolute measures) were measured on all specimens in the type series, with data for the primary type reported separately in brackets if necessary. The relative indices were measured on the primary type specimen only.

Results
Five new species were found in the undetermined material from BMNH, NMSA and SAMC. The key to and the descriptions of all species are provided below. Additional online dichotomous and matrix keys are available at www.waspweb.org.
-Clypeus smooth (a); frons with two submedian carinae, diverging on upper frons toward lateral ocelli (b); tergite 1 of female slender, more than 1.4x longer than apically wide (c) …………………………………………………………………………E. ghesquierei Benoit, 1951  Diagnosis (updated from Townes 1969 andGauld 1991) Small to large insects (fore wing length 6-25 mm), usually orange or yellow interspersed with black maculae; clypeus very small, not subdivided, often with a subapical ridge bearing median and/or lateral weak to strong tubercles; ventral margin of clypeus thin, slightly concave, often with lateral corners produced; mandible not twisted, stout, strongly constricted basally, then weakly tapered, apically bidentate with lower tooth pointed (may appear chisel-like when worn) and upper tooth blunt or chisellike; occipital carina complete to nearly absent, when ventrally present joining hypostomal carina above mandibular base; hypostomal carina strongly raised above mandible base; subocular sulcus absent, but malar area granulate; pronotum long, mid-dorsally with a deep invagination and with thin margin projecting beyond invagination; antero-lateral margin of pronotum broadly rounded in front, its lower corner acute and slightly in-turned; epomia weak to moderately strong, contiguous with and diverging from anterior pronotal margin; mesoscutum with strong transverse rugosities; notauli anteriorly strong and meeting in centre of mesoscutum, defining an anteriorly abruptly rounded median lobe; mesopleuron moderately long, epicnemial carina most often present laterally and reaching to or above lower corner of pronotum, its dorsal end evanescent; mesopleural suture weakly angled centrally; submetapleural carina weak to strong, more or less complete; propodeum of moderate length, without carina dorsally but pleural carina distinct; tarsal claws simple, large; fore wing with areolet open, 2m-cu slightly basal to distinctly apical to rs-m; hind wing with distal abscissa of Cu present, joining Cu&cu-a near or at junction with M; mid trochantellus with a ventral longitudinal ridge; metasoma moderately slender, tergites smooth to finely sculptured; tergite 1 fused with its sternite and without glymma; apical margins of tergites 3-5 hardly to strongly concave; female with sternites 2-4 (but see E. brianfisheri sp. nov.) with an anterior pair of tubercles, and with an apical truncate horn-like process on last tergite, ovipositor stout, laterally compressed, 4-5x longer than hind tibia; male with metasoma slenderer and subgenital plate elongate, posteriorly rather concave. (Yu et al. 2012) Epirhyssa is mostly circumtropical with some Far-Eastern species occurring up to Northern Japan; it includes 113 valid species with only six reported from the Afrotropical Region, to which we add here five new species.

Differential diagnosis
Species characterized by the exceptional mottled coloration and the presence of antero-basal tubercles on sternite 1 (cf. taxonomic remarks). All other species of Epirhyssa lack the antero-basal tubercles.

Etymology
Dedicated to Brian Fisher, friend and expert organizer of expeditions into central Africa, including the CAR expedition that discovered this species.
Color. Head pale yellow with black to dark brown parts: mandible, malar space, median tubercle of clypeus, a thin mid-longitudinal line on upper face, frons, vertex, and most of occiput; mesosoma pale yellow with most of mesoscutum black, and testaceous to brown parts: anterior margin of pronotum, propleuron, most of mesopleuron but subtegular ridge and two lateral patches, mesosternum, ventral margin of metapleuron and anterior third of propodeum; metasoma dark brown with pale yellow markings: tergites 1-2 medially, tergite 3-4 posteriorly; sternites pale yellow, more or less extensively testaceous anteriorly; antenna dark brown with scape somewhat pale maculated; ovipositor sheath brown; fore and mid legs testaceous with coxae and tibiae mostly pale yellow, hind leg testaceous with coxa partly pale yellow and femur with an outer longitudinal pale yellow stripe; wings hyaline, fore wing anteriorly infuscate from pterostigma to apex. Head. Densely setose with long hairs, hairs shorter on upper back head; face rugulose punctate, strongly protruding medially; clypeus sparsely punctate, subapical ridge with median tubercle strong and lateral tubercle weak, ventral margin strongly produced laterally; mandible stout; frons transversely rugose with a blunt Y-shaped mid-longitudinal carina below median ocellus, inner margins of toruli not expanded backwards; vertex and temple sparsely punctate but inter-ocellar area rugose; ocellar triangle wide; occipital carina mid-dorsally interrupted; antenna with 33 flagellomeres.
MesosoMa. Entirely covered with dense and long hairs; mesosoma moderately densely punctate, but mesonotum deeply transversely striate, anterior half of pronotum smooth and mesopleuron somewhat transversely strigose medially; epomia moderate; epicnemial carina hardly reaching level of mesopleural pit; apex of subtegular ridge convex, not flanged laterally; submetapleural carina strong, slightly and evenly narrowed toward apex.
Wings. Fore wing with 2m-cu opposite rs-m, cu-a almost opposite Rs&M, and Rs strongly bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a close to junction with M, with a basal group of two hamuli on distal abscissa of R1.

Male
Unknown.

Distribution
Central African Republic.

Taxonomic remarks
The presence of tubercles on sternite 1 is quite unexpected in Epirhyssa, while it is one of the features defining the Oriental genus Triancyra Baltazar, 1961. However, we refrain from placing this new species in Triancyra for the following reasons. Besides the geographical separation from the known distribution area of Triancyra, the majority of morphological characters exhibited by this new species do not fit the current generic definition for Triancyra. For example, E. brianfisheri sp. nov. exhibits subequal mandibular teeth (vs. upper tooth narrower in Triancyra), a pterostigma that is long and slender (vs. up to 5x longer than high), hind wing with a basal group of two hamuli (vs. usually three), tergite 1 long and slender (vs. stout, 1.3x longer than wide) (Townes, 1969). Hence, we are of the opinion that the species fits more comfortably within Epirhyssa than in Triancyra, but the possession of additional tubercles in Epirhyssa species underlines the need for a global phylogenetic revision of the whole subfamily. Epirhyssa is indeed poorly defined and probably not monophyletic (G. Broad, pers. comm.). concave, laterally flanged; fore wing with 2m-cu slightly apical to rs-m; tergite 1 slender; tergites 1-5 smooth, following tergites densely and finely punctate; apical margins of tergites 3-7 strongly concave. CT 2.7; ML 0.5; POL 1.3; OOL1.6; Fl 1 4.2; Fl 15 1.8; T1 1.7; OT 5.2.

Differential diagnosis
A mostly bright yellow species with hyaline wings, otherwise characterized by the combination of the punctate clypeus, the concave and flanged subtegular ridge, and the sharp mid-longitudinal carina on the frons, which separates this species from other yellow species with hyaline wings (these species have a strigose or hardly sculptured clypeus, and all of them except E. uelensis have no flange on the subtegular ridge).

Etymology
Dedicated to Gavin Broad for his constant support and his most valuable advice.
Head. Face rugulose punctate, moderately protruding dorsally; clypeus punctate, with a moderate subapical median tubercle, ventral margin strongly produced laterally; mandible stout; frons smooth; inner margins of toruli expanded backwards into two converging lamellar carinae, carinae then fused into a sharp mid-longitudinal carina reaching median ocellus; frons also with an additional lateral curved carina from posterior margin of torulus to next to lateral ocellus; inter-ocellar area rugose, remainder of vertex and temple finely punctate; occipital carina mid-dorsally evanescent; antenna with more than 35 flagellomeres (apices broken).
Wings. Fore wing with 2m-cu slightly apical to rs-m, cu-a slightly apical to Rs&M, and Rs strongly bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a close to junction with M.

Male
Unknown.

Differential diagnosis
A mostly bright yellow species with hyaline wings, otherwise characterized by the combination of the pair of submedian carinae on the frons diverging towards the lateral ocelli and the slender tergite 1. The other yellow species with hyaline wings have a stouter tergite 1 in the female, less than twice as long as apically wide. Color. Bright yellow overall, with black markings on mandible, vertex, upper occiput, and mesoscutum margins; antenna and ovipositor sheath dark brown; wings hyaline, apex hardly infuscate, venation pale brown.
Wings. Fore wing with 2m-cu slightly apical to rs-m, cu-a slightly apical to Rs&M, and Rs weakly bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a close to junction with M.
Similar to female but tergite 1 slenderer (T1 2.5); the two males from Cameroon are significantly lighter, without dorsal black markings.

Differential diagnosis
A mostly bright yellow species with hyaline wings, otherwise characterized by the combination of the black mesosternum, vein 2m-cu slightly basal to rs-m and the stout tergite 1 (at least in the female). All other yellow Afrotropical Epirhyssa species have the mesosternum concolorous with the remainder of the mesosoma and the vein 2m-cu slightly apical to rs-m.

Material examined
Holotype Color. Bright to dull yellow overall, with metasoma fading to brown toward apex, and with black markings: mandible, ventral margin of clypeus, ocellar area (macula connected to eye margin), occiput mid-dorsally, mesosternum, and a median macula on each mesoscutal lobe; antenna and ovipositor sheath dark brown; wings hyaline, slightly infuscate apically, venation pale brown.
MesosoMa. Mesosoma shallowly and moderately densely punctate, but mesonotum deeply transversely striate and anterior half of pronotum smooth; epomia moderate; epicnemial carina long, its evanescent dorsal end reaching above level of mesopleural pit; apex of subtegular ridge convex, not flanged laterally; submetapleural carina anteriorly expanded, then distinctly narrowed toward apex.
Wings. Fore wing with 2m-cu slightly basal to rs-m, cu-a slightly apical to Rs&M, and Rs weakly bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a close to junction with M.

Male
Unknown.

Differential diagnosis
Species characterized by its coloration, with apical half of metasoma black, wings yellowish with black patterns; otherwise characterized by the combination of the sparsely punctate face, the absence of subapical protuberances on the clypeus, the ventral margin of the clypeus not produced laterally, and the epicnemial carina nearly absent laterally. It is the only yellow Afrotropical species with banded wings.

Description Female
Unknown.
Color. Bright yellowish orange overall with dark brown to black markings: apical 2/3 of mandible, frons, vertex, temple, hind leg from femur and metasoma from tergite 4; flagellum dark brown; wings yellowish, apically strongly infuscate, fore wing with an additional transverse infuscate stripe at pterostigma level, venation yellow.
Head. Face sub-quadrate, sparsely punctate, barely protruding dorsally but with a short mid-longitudinal ridge near toruli; clypeus mostly smooth with some punctures along dorsal margin, without distinct subapical tubercle, ventral margin truncate; mandible stout, both teeth truncate and chisel-like; upper head quite smooth; frons with a blunt Y-shaped mid-longitudinal carina below median ocellus, inner margins of toruli not expanded backwards; occipital carina mid-dorsally evanescent; antenna with 34-37 flagellomeres.
Wings. Fore wing with 2m-cu opposite rs-m, cu-a distinctly apical to Rs&M, Rs moderately bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a at its anterior third, remote from junction with M.

Differential diagnosis
A mostly bright yellow species with hyaline wings, otherwise characterized by the combination of the flat and sparsely punctate face, the pair of submedian carinae on the frons and the absence of the epicnemial carina on the mesopleuron. The lateral part of the epicnemial carina is distinct in every other yellow species with hyaline wings. Color. Bright yellow overall with infuscate to black markings: mandible, inter-ocellar area (macula connected to eye margin), dorsal margin of occiput, mesoscutal lobes mid-longitudinally, and scutoscutellar groove; antenna and ovipositor sheath mostly dark brown; wings nearly hyaline, apically slightly infuscate, venation testaceous.

Material examined
Head. Face sparsely punctate, almost flat; clypeus smoothly sculptured with moderate lateral and median subapical tubercles, ventral margin moderately produced laterally; mandible stout; upper head quite smooth to moderately and shallowly punctate, inter-ocellar area somewhat rugose; frons with a pair of submedian carinae, carinae abruptly diverging below median ocellus and following anterior margin of vertex, inner margins of toruli hardly produced backwards; occipital carina mid-dorsally interrupted; antenna with 36 flagellomeres.
MesosoMa. Mesosoma shallowly and moderately densely punctate, but mesonotum transversely striate and anterior half of pronotum smooth; epomia weak; epicnemial carina absent except for a short ventral remnant; apex of subtegular ridge convex, not flanged laterally; submetapleural carina strong and even all along.
Wings. Fore wing with 2m-cu slightly apical to rs-m, cu-a slightly apical to Rs&M, and Rs moderately bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a close to junction with M.

Differential diagnosis
Highly distinctive species of mottled color and large to very large size; otherwise characterized by the combination of the flat and sparsely punctate face, the sharp mid-longitudinal carina on the frons, the absence of a subapical ridge on the clypeus, and the very long ovipositor. No other known Epirhyssa species shares this color pattern. Color. Head yellow with mandible black and lower gena, vertex and upper occiput brownish testaceous; mesosoma black to dark brownish testaceous interspersed with yellow markings: pronotum dorsally and ventrally, mesopleuron anteriorly and posteriorly, and mesoscutum, scutellum, metanotum and propodeum centrally; legs testaceous to dark testaceous with fore and mid coxa yellow; metasoma light to dark testaceous, tergites 1-5 with apico-lateral large yellow spots; antenna and ovipositor sheath dark brown; wings nearly hyaline, apically infuscate, venation dark brown.

Holotype
Head. Face subquadrate, transversely striate and hardly bulging medially; clypeus shallowly and sparsely punctate, without subapical tubercle, ventral margin strongly produced laterally; mandible stout; upper head quite smooth; inner margins of toruli expanded backwards into two converging lamellar carinae, carinae then fused into a sharp mid-longitudinal carina reaching median ocellus; frons also with an additional lateral curved carina from posterior margin of torulus to next to lateral ocellus; occipital carina mid-dorsally interrupted; antenna with 41-43 flagellomeres.
MesosoMa. Mesosoma shallowly and moderately densely punctate, but mesonotum transversely striate and anterior half of pronotum smooth; epomia indistinct; epicnemial carina reaching lower level of speculum, mesopleural pit indistinct; apex of subtegular ridge convex, not flanged laterally; submetapleural carina moderate and even all along.
Wings. Fore wing with 2m-cu opposite rs-m, cu-a slightly apical to Rs&M, and Rs short and moderately bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a at junction with M.

Male
Unknown.

Distribution
Democratic Republic of Congo. New record: Cameroon.

Comments
The species is only known from two female specimens. They exhibit a remarkable variation in size, the BMNH specimen being one third smaller than the impressively large MRAC holotype.

Differential diagnosis
Pale yellow species of relatively small size, otherwise characterized by the combination of the weak mid-longitudinal carina on the frons, the entirely punctate tergite 2 and the slender tergite 1.

Etymology
Refers to King Shaka Zulu, another kind of population regulator of the Zululand region. He would certainly have been proud of giving his name to an ichneumon.
Wings. Fore wing with 2m-cu slightly apical to rs-m, cu-a slightly apical to Rs+M, Rs moderately bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a close to junction with M.
MetasoMa. Tergite 1 moderately slender, sparsely and shallowly punctate; tergite 2 and following densely punctate; apical margins of all tergites straight. Some other yellow species also sometimes have some punctures on tergite 2 (E. tombeaodiba), but the first tergite of the female is then distinctively stouter.

Male
Unknown.

Differential diagnosis
Bright yellow species with wings hyaline, otherwise characterized by the combination of the entirely punctate tergite 2, the weak mid-longitudinal carina on the frons and the stout tergite 1. It is the only known yellow Epirhyssa species with both a distinctly sculptured clypeus and a stout tergite 1.

Etymology
Refers to Mrs Jackson's ambiguous marital status as reported by label data. In the Duala language, "tómbea ó dibá" means "to get married" for a woman.
MesosoMa. Mesosoma shallowly and moderately densely punctate, but mesonotum deeply transversely striate and anterior half of pronotum smooth; epicnemial carina reaching level of mesopleural pit; apex of subtegular ridge convex, not flanged laterally; submetapleural carina slightly enlarged anteriorly, then evenly narrowed toward apex, strongly notched at anterior third in one paratype.
Wings. Fore wing with 2m-cu distinctly apical to rs-m, cu-a barely apical to Rs&M, and Rs moderately bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a shortly below junction with M.

Differential diagnosis
A mostly bright yellow species with hyaline wings, otherwise characterized by the combination of the concave subtegular ridge, the mid-longitudinal carina on the frons and the stout tergite 1 of the female.
Color. Bright yellow overall, sometimes with infuscate to black mid-longitudinal stripes on tergites 5-7, and black markings: mandible, ocellar area (macula connected to eye margin), upper occiput and mesoscutum but lateral margins and a large central macula, sometimes apex of scutellum, basal margin and apex of propodeum; ovipositor sheath reddish testaceous; wings hyaline, weakly infuscate apically, venation brown.
Head. Face rugulose-punctate and moderately protruding dorsally; clypeus smoothly sculptured, with a strong subapical median tubercle, ventral margin moderately produced laterally and medially; mandible stout; frons nearly smooth with sparse fine punctures; inner margins of toruli expanded backwards into two converging weak carinae, carinae then fused into a mid-longitudinal carina reaching median ocellus; frons also with an additional lateral curved carina from posterior margin of torulus to next to lateral ocellus; vertex and temples sparsely punctate, inter-ocellar area somewhat rugose; occipital carina mid-dorsally evanescent; hypostomal carina strongly raised above mandibular base; antenna with 32-34 flagellomeres.
MesosoMa. Mesosoma shallowly and moderately densely punctate, but mesonotum deeply transversely striate and anterior half of pronotum smooth; epomia moderate; dorsal faint apex of epicnemial carina nearly reaching level of mesopleural pit; apex of subtegular ridge concave, weakly to distinctly flanged laterally; submetapleural carina slightly and evenly narrowed toward apex.
Wings. Fore wing with 2m-cu slightly apical to rs-m, cu-a slightly apical to Rs+M, Rs strongly bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a close to junction with M.

Distribution
Democratic Republic of Congo. New record: Cameroon.

Differential diagnosis
A species with unique color pattern, with most of mesosoma black, metasoma orange and wings blackish with a subapical light patch; otherwise characterized by the sparsely punctate face, the truncate ventral margin of the clypeus and the stout tergite 1 of the female.

Etymology
Dedicated to Claire Villemant, MNHN curator, hymenopterologist and ichneumonomaniac, adviser, teacher, supporter, coach and friend. Color. Head and pronotum yellowish-orange with mandible and ocellar area black; remainder of mesosoma blackish testaceous; metasoma orange; fore leg and mid leg from tibia yellowish orange, remainder of legs blackish testaceous; antenna and ovipositor sheath brown; wings strongly infuscate but with large subapical and small mid-dorsal pale yellowish patches on fore wing.
Head. Face sparsely punctate, almost smooth laterally, and moderately protruding dorsally; clypeus smooth, with a moderate subapical median tubercle, ventral margin truncate; mandible stout; frons laterally smooth, medially transversely striate; inner margin of toruli expanded backwards into two weak sinuate submedian carinae, carinae then diverging and reaching lateral ocelli; frons also with an additional lateral curved carina from posterior margin of torulus to next to lateral ocellus; vertex and temples almost smooth, inter-ocellar area somewhat rugose; occipital carina mid-dorsally evanescent; hypostomal carina strongly raised above mandibular base; antenna with 36 flagellomeres.
MesosoMa. Mesosoma finely, sparsely and shallowly punctate, but mesonotum transversely striate and pronotum, speculum area and propodeum medially smooth; epomia very weak; dorsal faint apex of epicnemial carina reaching level of mesopleural pit; apex of subtegular ridge convex, not flanged laterally; submetapleural carina moderate and even all along. Wings. Fore wing with 2m-cu slightly apical to rs-m, cu-a slightly apical to Rs+M, Rs moderately bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a at its anterior third, remote from junction with M.

Male
Unknown.

Distribution
Nigeria.
Genus Megarhyssa Ashmead, 1900Thalessa Holmgren, 1859: 122. Megalorhyssa Shulz, 1906: 115. Eurhyssa Derksen, 1941: 721. Diagnosis (updated from Townes 1969 Large to very large insects (fore wing length 10-30 mm); clypeus small, transversely rectangular, ventral margin laterally and sometimes medially bluntly produced; occipital and hypostomal carinae joining above mandible base; mandibular teeth subequal, lower tooth pointed and upper tooth more or less chisel shaped; propodeum of moderate length, without carina dorsally but pleural carina distinct; fore wing with areolet closed except in occasional dwarf males, receiving 2m-cu within its apical half, pterostigma about 5.5x longer than wide; hind wing with distal abscissa of Cu present, joining Cu&cu-a near or at junction with M; mid trochantellus with a ventral longitudinal ridge; tarsal claws simple, large; tergite 1 fused with its sternite and without glymma; tergites 3-6 almost smooth to finely and sparsely punctate and with isolated aciculate areas; female with sternites 2-4 each with a pair of tubercles near anterior margin, and with an apical truncate horn-like process on last tergite; male with metasoma strongly depressed, gonosquama lanceolate, strongly depressed, with a sharp piliferous groove along inner lower margin and a short subapical piliferous groove on outer face. (Gauld 1984;Yu et al. 2012) Megarhyssa is mostly a Holarctic and Oriental genus, with one species introduced into Australia and New Zealand for biocontrol purposes, and a single species reported from the Afrotropical Region. Seyrig, 1937 Fig. 12 Megarhyssa babaulti kapangaensis Seyrig, 1937: 116. Megarhyssa babaulti kapangaensis var. rubra Benoit, 1951: 385. Megarhyssa babaulti kapangaensis var. rubrerrima Benoit, 1951: 385.

Diagnosis
Head orange with a black part of variable extent; mesosoma orange, posterior third sometimes dark brown; metasoma mostly black with pale yellow or orange markings of variable extent; flagellum twocolored, basally black and apically orange; wings blackish with lighter patch of variable extent; face moderately punctate to smooth, flat; clypeus smooth, with median subapical tubercle weak, ventral margin strongly produced laterally; frons smooth with a pair of submedian carinae diverging toward lateral ocelli; epicnemial carina laterally absent; subtegular ridge convex; fore wing with areolet strongly petiolate, receiving 2m-cu at its distal apex, opposite 3rs-m; tergite 1 very stout; tergites 1-4 smooth or mostly so, following tergites finely and densely punctate; apical margins of tergites 3-5 strongly concave. CT 3.4; ML 0.6; POL 1. Color. Head orange with isolated black parts to almost entirely black; antenna basally black, fading to orange from flagellomere 12; mesosoma orange, posterior third varying from orange to entirely black; legs orange with mid and fore legs variably orange to dark brown; metasoma black with tergites 1-3 varying from orange to black, tergite 4 and following largely pale yellow laterally, sternites pale yellow; ovipositor sheath black, apical half fading to reddish-orange; wings blackish with lighter yellowish parts of variable extension (color variation : Seyrig 1937;Benoit 1951).
MesosoMa. Mesosoma finely and moderately densely punctate, but mesonotum deeply transversely striate and anterior half of pronotum smooth; epomia indistinct; epicnemial carina absent except for a faint ventral remnant; apex of subtegular ridge convex, not flanged laterally; submetapleural carina barely expanded anteriorly and evenly narrowed toward apex.
Wings. Fore wing with areolet strongly petiolate, receiving 2m-cu at its apex, cu-a strongly apical to Rs&M, Rs strongly bowed forwards; hind wing with distal abscissa of Cu joining Cu&cu-a shortly above middle of Cu&cu-a.

Male
Unknown.

Distribution
Democratic Republic of Congo.

Discussion
We face here an apparent paradoxical observation: despite the historical general interest they have received and their expected high diversity in the tropics, very few species of Rhyssinae have been described in Africa, and the African and European museums house only scarce, undetermined material. Discussing the zoogeographical history of Epirhyssa in the Neotropical region, Porter (1978Porter ( , 1982 showed that their abundance, distribution and phenology are strongly related to the humidity level: dry periods and arid areas are major ecological obstacles for Rhyssinae, hence they are expected to be highly diversified in lowland tropical humid forests. Nevertheless, the collection efforts carried out by the Iziko South African Museum in Gabon, Uganda, Central African Republic and South Africa (Table 1) produced only two specimens, despite the fact that a large proportion of the central African sampling took place in lowland rainforest. On the other hand, examination of the mere 15 undetermined specimens gathered for this study revealed that half of them belonged to five new species, four of them being singletons.
Thus, Rhyssinae appear very rare though greatly diversified in the Afrotropical region. Their rarity may be explained by ecological hypotheses. Rhyssinae are indeed known to parasitize primarily Siricidae and Xiphydriidae in the Northern Hemisphere (Yu et al. 2012), while these families are poorly represented in the tropics. Virtually nothing is known about the ecology of Epirhyssa, but as some Holarctic Rhyssinae are also known to exploit Cerambycidae, they have been hypothesized to develop mostly on woodboring coleopteran larvae (Gauld 1991). This ecological niche, however, is also exploited by other taxa: Braconinae, for example, have been diversifying in Africa for a long time, and one plausible hypothesis is that the competition was disadvantageous for Rhyssinae (G. Broad, pers. comm.).
Somewhat contradictory with his own observations, Porter (1978Porter ( , 1982 stated that the largest lowland rainforest of the world in the Amazon Basin was rather depleted of Rhyssinae. Following their own collection efforts in this region, Sääksjärvi et al. (2004) and Veijalainen et al. (2013), however, showed that Porter's biogeographical assumptions were mainly influenced by sampling bias: intensive local collection efforts are needed to uncover most of the diversity of Rhyssinae and other hymenopteran groups. Sääksjärvi et al. (2004) report a sampling effort of 185 Malaise trap months resulting in 12 new species. These figures of return relative to sampling effort appear similar to ours from tropical areas of Africa. We predict that most of the Afrotropical diversity of Rhyssinae has still to be discovered, but intensive efforts of long-term sampling are required to unveil them. specimens as part of the WWF-US CAR field expedition conducted in 2001. Disclaimer: the attributed names referring to historical personages are purely functional: neither of the authors approves, nor supports any aspect of the atypical policy of King Shaka Zulu nor any other monarch of the 19 th Century.