Revision of Distictus Townes, 1966 (Hymenoptera, Ichneumonidae, Cryptinae), with descriptions of ten new species

The Neotropical Distictus Townes, 1966 is diagnosed, redescribed and its species revised. A neotype is designated for the type species, D. tibialis (Brullé, 1846). The genus is characterized mainly by having the body subcylindric; clypeal margin with median tooth; areolet medium-sized, pentagonal, with crossvein 3r-m distinct; first metasomal tergite short and stout, with anterolateral tooth. Distictus aurantium Santos & Aguiar, 2008 is shown to lack some of these character states and is transferred to Mallochia Viereck, 1912. A total of 12 valid species are recognized, ten of which are new: D. apaensis sp. nov., D. ardens sp. nov., D. asterios sp. nov., D. ateles sp. nov., D. caligaris sp. nov., D. commatus sp. nov., D. daelus sp. nov., D. notabilis sp. nov., D. paratibialis sp. nov. and D. terrosus sp. nov. Other valid species are D. tibialis and D. mexicanus Kasparyan & Ruíz-Cancino, 2005. All species are described and illustrated. New distribution records, maps and separate keys for females and males of the species are provided.

The detailed species comparisons in the 'Comments' sections aim to provide a robust and objective style of defense for each taxon, by showing explicitly what the differences are, instead of leaving the strenuous (and, in practice, overtly averted) task of comparing descriptions to the user. The comparative differences are carefully ordered in decreasing order of perceived relevance. The number of characters which differ between any two species were also computed, and are presented as the number of structural (qualitative) differences between the respective descriptions.
When potentially ambiguous, colour names are followed by an equivalent RGB formula, as determined from digital pictures of the studied specimens, according to procedures described by Aguiar (2005b).
According to Pecci-Maddalena & Lopes-Andrade (2018), the common but elusive denomination "Reprêsa Rio Grande" (Brazil), here found on the labels of some D. ateles sp. nov. (including the holotype), was given to only one of several streams dammed at the time, and currently is part of the set of reservoirs of the 'Ribeirão das Lajes' dam, and its whole area is an ecological reserve. The reservoir comprises areas in Piraí and Rio Claro, both in the state of RJ. SUPELETO F.A. et al., Revision of Distictus Townes, 1966 (Hymenoptera, Ichneumonidae) emarginate at midlength, apex truncate, with median tooth; apical margin laterally projected. Antenna with 24-31 flagellomeres; flagellum gradually tapered apically; apical flagellomere blunt, with narrow apical truncation. Supra-antennal area ventrally slightly to distinctly concave, usually with distinct median line. Occipital carina strong, sharp, sometimes dorsally weakened, meeting hypostomal carina far from mandible base. Temple and gena in lateral view moderately wide.
MeSoSoMa. Dorsal margin of pronotum regular, not swollen; epomia delicate or stout, usually ending far from margin of pronotum. Mesoscutum subcircular to ovoid, 0.89-1.26 × as long as wide, anteriorly moderately convex, posteriorly flattened, shiny or matte, almost always densely covered with short  Townes, 1966 (Hymenoptera, Ichneumonidae) hairs, usually with weak to distinct longitudinal wrinkles on area enclosed by end of notauli; notaulus moderately impressed, weakly to distinctly convergent, reaching 0.43-0.84 of mesoscutum length, bearing weak to distinct striae. Epicnemial carina complete to reaching only 0.7 of distance to subalar ridge, irregular or sinuous or approximately uniformly curved. Sternaulus distinctly sinuous, complete, even if posterior 0.4 almost indistinct; usually moderately deep (except deeply impressed in D. daelus sp. nov.), bearing weak to distinct vertical wrinkles. Mesopleural suture weakly to distinctly carinulate inside. Median portion of postpectal carina absent. Posterior margin of metanotum without teeth-like projections. Propodeal furrow moderately deep, narrow, forming a polished smooth trough. Juxtacoxal carina vestigial or represented by short ridge. Pleural carina absent. Fore tibia moderately swollen. On all legs, fourth tarsomere apically bilobed, with strong apical group of bristles.
The similarity between Distictus and Mallochia had been noticed by Kasparyan & Ruíz-Cancino (2005: 109), who went as far as to name a species of the latter genus as M. distictus (Kasparyan & Ruíz-Cancino, 2008). In fact, examination of additional comparative material showed that the species described as Distictus aurantium by  is likely to be part of Mallochia (see below). Following the generic delimitation presented in this paper, Distictus can be objectively separated from Mallochia (including D. aurantium) based on the following differences: 1. First tergite with conspicuous anterolateral tooth that is rounded or angular in dorsal view (Fig. 13B); areolet medium-sized, at least slightly longer or slightly shorter than the section of crossvein 2m-cu above the bulla ( Genus Mallochia Viereck, 1912 Mallochia aurantia  comb. nov.

Comments
The considerable differences between the type species Distictus tibialis and D. aurantium Santos & Aguiar have already been stressed in Santos & Aguiar (2008: 32, 38). Those differences prompted the authors to include both species in a phylogenetic analysis based on 65 morphological characters, including 19 outgroup taxa, mostly from the group the genus was supposed to belong to, the subtribe Gabuniina (Gabunia genus group sensu Santos 2017). The two species were recovered as sister groups and hence classified within the same genus. However, examination of further comparative material of Distictus and Mallochia shows that several species of the latter genus show character states similar to species of Distictus (see 'Comments' section for the genus above). The characters that consistently separate the two genera are precisely those that set D. aurantium apart from the other species of the genus, such as T1 without anterolateral tooth, fore wing crossvein 3r-m absent and vein 2Cua < 0.60 × as long as crossvein 2cu-a. In fact, the species is quite similar to specimens of the Nearctic Mallochia strigosa (Cresson, 1872). Hence, Distictus aurantium is hereby transferred to Mallochia.
Nomenclature Yu et al. (2012) changed the neutral specific epithet aurantium to the masculine aurantius, to match Distictus, which is masculine. The ICZN (1999) states, in Article 34.2.1, that "If a species-group name is a noun in apposition its ending need not agree in gender with the generic name with which it is combined and must not be changed to agree in gender with the generic name". The epithet was originally intended as a name in aposition, but this was not stated, making the emendation to aurantius acceptable. In an equivalent action, the epithet is now changed to aurantia to match Mallochia, which is feminine.   12D); supra-clypeal area without three blackish marks that are almost connected centrally to form an inverted Y, only with two oblique blackish marks on ventral 0.3 (Fig. 12A); median tubercle of clypeus small; orbital band shortly interrupted on malar space, nearly fused at eye margin (Fig. 12A); spiracle of T1 slightly prominent; propodeum sublaterally with distinct yellow spot basad tranverse carina (Fig. 7C)

Etymology
The specific epithet is a reference to the Apa Apa Ecological Reserve, where the holotype was collected.

Material examined
Total of 1 specimen.  Townes, 1966 (Hymenoptera, Ichneumonidae) Colour. Head, mesosoma and metasoma black, dark brown and yellow. Head black; basal 0.5 of mandible, labrum, clypeus except lateral corners and area around median tooth, and most of supraclypeal area yellow. Supra-clypeal area centrally with two small blackish marks. Palpi dark brown. Orbital band yellow, complete, covering almost entire width of gena on its ventral 0.3. Antenna mostly dark brown; scape ventrally with very small yellowish spot; f7-11 entirely white, f6 almost entirely white. Mesosoma black; pronotum (except median longitudinal stripe), propleuron, central spot on mesoscutum, tegula, scutellum, postscutellum, subalar ridge, part of epicnemion, most of ventral portion of mesopleuron, hypoepimeron, dorsal division of metapleuron, posterior mark covering 0.2 of metapleuron and sublateral marks on posterior area of propodeum yellow. Fore and mid coxae pale yellow, dorso-apically with small brown spots; fore first trochanter dorsally blackish, ventrally yellow; mid first trochanter marked with orange and blackish; fore and mid second trochanter orange; fore and mid femora orange, dorsally with longitudinal blackish marks; fore and mid tibia and tarsi brownish, tarsi blackish towards apex. Hind coxa mostly yellow, ventrally somewhat orange, laterally with longitudinal brownish stripe on basal 0.75, dorsally with brown mark on apical 0.6; hind trochanters and base of femur marked with orange and blackish; remainder of hind femur and tibia blackish, except extreme base of tibia brown; extreme base of hind t1 and t5 blackish; remainder of hind tarsus whitish. Wings hyaline. Metasoma mostly yellow; T1 dorsally dark brown on median 0.4; T2-8 dark brown on anterior 0.5-0.7.

Male
Unknown.

Comments
This species can be confused with a Cyclaulus, but it has a weak lateral expansion on T1 (vs absent in Cyclaulus), and the petiolar spiracle is placed basad to the midlength (vs apicad). Structurally, D. apaensis sp. nov. differs from all other species in the genus by having four exclusive features: 1m-cu about as long as vein 1Rs+M; fore wing vein 1M+Rs more or less uniformly curved; supra-antennal area dorsally with distinct median line, ventrally fading; and scuto-scutellar groove shallow. In colour, it can be isolated by having lateral yellow marks on the mesoscutum (Fig. 4B).
The new species is most similar in structure to D. tibialis, from which it differs in 49 features, of which the most important are as follows: posterior area of propodeum strigate (vs rugulose); apical area of clypeus narrow (vs moderately long); fore wing vein 3-M distinctly longer than 2-M (vs about as long as 2-M); crossvein 1cu-a weakly convex (vs convex); scuto-scutellar groove shallow and weakly carinulate (vs deep, distinctly carinulate); pronotum weakly striate along posterior margin and collar (vs distinctly striate along posterior margin and collar); sulcus between sternaulus and scrobe distinct (vs almost indistinct); sternaulus with weak vertical wrinkles (vs with distinct vertical wrinkles); ventral valve of ovipositor slightly overlapping dorsal valve (vs distinctly overlapping dorsal valve); ovipositor slightly downcurved (vs straight).
Colour. Head and mesosoma mostly black, metasoma reddish-orange. Head black; small spot on base of mandible and labrum except central mark bright yellow. Palpi dark brown. Orbital band narrow, distinct only on about 0.5 of supra-clypeal and supra-antennal areas and on dorsal 0.4 of gena; f7-9 entirely white, f6 and f10 mostly white, f11 with small white mark. Mesosoma black; anterior apex of pronotal collar, small marks on dorsal margin of pronotum, tegula, scutellum and over propodeal crests bright yellow. Fore and mid coxae black with small yellowish and orange marks; fore and mid first trochanters marked with blackish and orange; fore and mid second trochanters, femora, tibiae and t1-2 orange; fore and mid t3-5 blackish. Hind coxa trochanters and femur reddish-orange; hind tibia basal 0.1 orange, remainder of it black; basal 0.15 of t1, apex of t4 and t5 blackish; apical 0.85 of t1, t2-3 and base of t4 whitish. Wings moderately infuscate. Metasoma reddish-orange; T1 dorsally infucate with blackish, posteriorly with very narrow yellow stripe; T5-7 and S6 with sparse, small yellowish marks.

Male
Unknown.

Comments
This is the most distinctive species of the genus, at least in terms of colour pattern ( Fig. 5A-C). It can be readily recognized by having head and mesosoma almost entirely black, without the extensive yellow marks on the collar, dorsal margin of pronotum, mesoscutum, scutellum, postscutellum, meso-and metapleuron which are found in all other species of the genus. It is also the only species of Distictus with infuscate wings and the supra-clypeal area almost entirely black. Structurally, D. ardens sp. nov. differs from all other species in the genus by having four exclusive features: ventrolateral carina of T1 anteriorly indistinct; epomia complete; hind coxa coriarious-rugulose; and T2-8 with pilosity somewhat dense and more or less uniform. In spite of being a very distinctive species, its general morphology agrees quite well with the definition of the genus.

Distribution records
Peru.

Etymology
From the Latin 'asterios', meaning 'starry', in reference to the multiple small yellow spots on a black background.
WingS. Fore wing vein 1M+Rs anteriorly straight, posteriorly curved; crossvein 1cu-a weakly convex, arising slightly basad of 1M+Rs; crossvein 1m-cu irregular, continuous with 1-Rs+M; vein 1-Rs+M with bulla placed near its midlength; vein 2Cua 1.33 × as long as crossvein 2cu-a; 3r-m partially spectral, about as long as 2r-m; vein 3-M distinctly longer than 2-M; AWH Colour. Head and mesosoma black with yellow marks; metasoma orange with black and yellow marks. Head black; small spots on base of mandible and center of clypeus, light yellow. Mouthparts dark brown. Orbital band briefly interrupted on malar space, distinctly wider on supra-clypeal area and ventral portion of gena, but never covering entire width of gena. White band on flagellum starting with small apical mark on f4. Mesosoma black; small marks on dorsal and ventral portions of collar, narrow mark on dorsal margin of pronotum, central spot on mesoscutum, part of tegula, scutellum, part of postscutellum, subalar ridge, small central mark on mesopleuron, dorsal portion of hypoepimeron, most of dorsal division of metapleuron, and small sublateral marks on posterior area of propodeum light yellow. All coxae black with small yellow spots, on mid coxa proportionally larger, on hind coxa placed dorso-basally; all first trochanters marked with orange and blackish; all second trochanters orange; fore and mid femora orange with dorsal dark marks, on mid femora a distinct blackish stripe; fore and mid tibiae deep yellow; fore and mid tarsi basally yellow, blackish towards apex; hind femur and tibia blackish, except apex of femur and base of tibia orange; basal 0.4 of t1, most of t4 and t5 blackish; apical 0.6 of t1, t2-3 and part of t4 white. Wings hyaline. Metasoma T1 dark brown, laterally partially light brown, posterior 0.2 yellow; T2 blackish, dorsally with posterior yellow stripe; T3-8 orange, T3 slightly infuscate with blackish marks and with narrow posterior yellow mark. Sternites orange.

Male
Unknown.

Comments
Structurally, D. asterios sp. nov. differs from all other species in the genus by having three exclusive features: hind coxa coriarious; fore wing vein 3r-m partially spectral; supra-antennal area ventrally and around ocelli distinctly concave. In colour, it is unique by having very small yellow marks on the collar and mesopleuron (Fig. 6D).
The new species is structurally most similar to D. tibialis, from which can be separated by 43 features, of which the most important are as follows: posterior area of propodeum strigate (vs rugulose); anterior European Journal of Taxonomy 542: 1-64 (2019) transverse carina distinctly arched forwards (vs slightly and uniformly arched forwards); pronotum weakly striate along posterior margin and collar (vs distinctly striate); mesoscutum coriarious (vs punctate-coriarious); apical area of clypeus very narrow (vs moderately long); fore wing crossvein 1cua weakly convex (vs convex); subalar ridge narrow, elongate (vs moderately wide).

Distribution records
Ecuador.  Table 1 Etymology From the Greek 'ateles', meaning 'imperfect, unfulfilled', in reference to the short epicnemial carina.
Colour. Head and mesosoma black with yellow marks; metasoma mostly reddish. Head black; basal spot on mandible, clypeus and most of supra-clypeal area bright yellow. Supra-clypeal area with three blackish marks that are almost connected centrally to form an inverted Y. Mouthparts mostly yellow; apical two segments on maxillary palpus and three on labial palpus brownish. Orbital band shortly interrupted near torulus and on malar space, never covering entire width of gena; f6-9 entirely white, f5 and f10 almost entirely white, f4 with small white mark; f11-30 ventrally dark brown. Mesosoma black; collar, narrow mark on dorsal margin of pronotum, central spot on mesoscutum, tegula, scutellum, postscutellum, subalar ridge, central mark on mesopleuron, dorsal portion of hypoepimeron, dorsal division of metapleuron, oval mark covering 0.25 of metapleuron, elongate sublateral marks over propodeal apodeme and very small spot dorsad of spiracle of propodeum bright yellow. Fore and mid coxae mesally black, laterally mostly yellow; fore first trochanter dorsally blackish, ventrally yellow; mid first trochanter blackish; fore and mid second trochanters marked with ferruginous and blackish; fore and mid femora dorsally blackish, ventrally yellow; all tibiae deep yellow; fore and mid tarsi basally yellow, blackish towards apex. Hind coxa, trochanters and femur reddish; coxa with dorso-basal yellow spot encircled by blackish ring; hind femur apically blackish; tarsus light yellow. Wings hyaline. SUPELETO F.A. et al., Revision of Distictus Townes, 1966 (Hymenoptera, Ichneumonidae) Metasoma reddish, lighter towards posterior segments, T7-8 bright orange; T1 mostly blackish with basal 0.15 and apical 0.2 bright yellow; T2 with very narrow anterior blackish stripe.
Variation. Morphometric ranges can be seen in Table 1. Anterior transverse carina of propodeum sometimes laterally weak; face without distinct black marks; mandible mostly black (~70%), at most with as much as 50% yellow; malar space extensively black; ventral portion of fore tarsus apex yellow to as blackish as dorsal side; hind coxa sometimes marked with black around posterior yellow spot; apex of hind femur sometimes blackish. Shape and extension of yellow marks at mesopleuron and metapleuron slightly variable, with southernmost populations usually more extensively black. Specimen from Mangaratiba with propodeum anterolaterally almost impunctate; propodeal crest absent, not even indicated by a carina; hind wing vein Cub slightly sinuous (vs evenly arched in other specimens). Specimen from Óbidos with black marks on fore and mid coxa less extensive, no blackish marks on hind coxa, two ovoid yellow marks on anterior region of propodeum (faintly suggested in a few other specimens).
Variation. Antenna with 30-32 flagellomeres; T1LW 2.98-3.35; T1WW 1.63-2.06. Southern specimens with more extensive black marks at malar space, smaller spot on mesopleuron, mid first trochantellus and hind trochanters marked with black, hind femur dorsally and ventrally blackish (laterally orange; in one specimen femur entirely orange) and yellow spots at propodeum smaller and elongate; specimen from Sinop with fore femur dark mark partially orange (not entirely black), hind coxa apically reddish-brown (black in southern specimens), yellow posterior spot more extensive, reaching almost to coxa apex, basal yellow spots at propodeum faintly suggested; apex of T2 as a distinct yellow stripe; epicnemial carina sometimes almost reaching subalar ridge; scape rarely ventrally with yellow spot; crossvein 1cu-a sometimes arising a little basad of 1M+Rs; one specimen from Represa Rio Grande with yellow spot on metapleuron small (about half as large as in other specimens) and apex of T2 with more or less distinct yellow stripe; both specimens from this locality with T2 basally blackish, T3 basally fuscous. Specimen from Linhares with hind coxa entirely blackish under yellow mark, while in one specimen from RJ (FSCA), the coxa is black adjacent to a yellow mark and ventrally orange. In Brazil, specimens from MT and PA differ from those from the southeastern states (MG and ES) by having the metasoma in bright orange (249,178,004) (vs brownish orange to orange), T2 with a distinct posterior yellow stripe (vs absent) and yellow stripes on mesosoma in a distinctly brighter tone of yellow.

Comments
Structurally, D. ateles sp. nov. differs from all other species in the genus by having three exclusive features: epicnemial carina reaching only about 0.70 of distance to subalar ridge; median tubercle of clypeus large; and vein 2-Rs entirely tubular, though weaker apically. In colour, it can be isolated by having the supra-clypeal area with three blackish marks that are almost connected centrally to form an inverted Y (Fig. 7A) and the hind femur reddish, apically blackish.
The new species is most similar in colour and structure to D. notabilis sp. nov., from which it can be differentiated by having the supra-clypeal area with three blackish marks that are almost connected centrally to form an inverted Y (vs two short, oblique blackish marks ventrally); orbital band widely interrupted on malar space, broadly disconnected at eye margin (vs shortly interrupted, almost meeting at eye margin); very small yellow spot dorsad of spiracle of propodeum (vs large yellow marks dorsad European Journal of Taxonomy 542: 1-64 (2019) of spiracle); hind coxa with baso-dorsal yellow spot encircled by blackish ring (Fig. 7C-D) (vs yellow spot not encircled by blackish ring, Fig. 12D); and hind femur reddish, apically blackish (vs fully bright orange). Structurally, it differs from D. notabilis sp. nov. by 34 features, of which the most important are as follows: epicnemial carina reaching about 0.70 of distance to subalar ridge (vs 0.85); pronotum distinctly striate along collar (vs weakly striate); median tubercle of clypeus large and placed mostly on apical area (vs small, placed entirely on apical area); fore wing crossvein 1cu-a arising distinctly basad of 1M+Rs (vs a little basad of 1M+Rs); spiracle of T1 not prominent (vs slightly prominent); ovipositor straight ( The new species is similar in colour to D. tibialis, from which can be isolated by having the metapleuron with a distinct yellow mark (vs black); T1 mostly black (Fig. 7D) (vs orange, Fig. 15F); hind femur apically blackish (vs entirely reddish). Structurally, it differs in 50 features, of which the most important are as follows: posterior area of propodeum strigate and shiny (Fig. 7C) (vs rugulose, matte, Fig. 15F); metapleuron lineate (vs rugulose); mesoscutum densely punctate (vs punctate-coriarious); anterior transverse carina slightly arched forwards, medially more distinctly curved (vs slightly and uniformly arched forwards); median tubercle of clypeus large (vs small); epicnemial carina reaching about 0.70 of distance to subalar ridge, and more or less uniformly curved (vs reaching subalar ridge, irregular); areolet 0.45 × as high as wide (vs 0.31-0.38); anterior margin of propodeum medially very slightly concave (vs medially concave); spiracle of propodeum elongate (vs oval); SWL 1.25-2.05 (vs 1.11-1.55); propodeum sparsely pilose (vs moderately pilose).
Colour. Head and mesosoma black and yellow; metasoma mostly orange. Head mostly light yellow; apical 0.5 of mandible, supra-antennal area medially, vertex, occiput and posterior 0.2-0.5 of gena on its dorsal 0.4 black. Orbital band covering almost entire width of gena on its ventral 0.6. Antenna mostly dark brown; scape ventrally mostly bright yellow; f10-21 entirely white, f9 and f22 mostly white. Mesosoma black; collar, dorsal margin of pronotum, propleuron, central spot on mesoscutum, tegula, scutellum, postscutellum, subalar ridge, central mark on mesopleuron, hypoepimeron, dorsal division of metapleuron and sublateral marks covering most of posterior area of propodeum light yellow. Fore and mid coxae and first trochanters light yellow; fore and mid second trochanters and femora ventrally yellowish, dorsally light fuscous on fore leg, orange on mid one; fore and mid tibia yellowish; fore SUPELETO F. A. et al., Revision of Distictus Townes, 1966 (Hymenoptera, Ichneumonidae) tarsus basally yellowish, brownish towards apex; mid tarsus brownish. Hind coxa orange, with dorsobasal yellow spot and sparse blackish marks; hind first trochanter marked with orange, blackish and yellow; second trochanter and femur orange, extreme apex of femur blackish; basal 0.7 of hind tibia deep yellow, apical 0.3 blackish; basal 0.3 of hind t1 and apex of t5 blackish; remainder of tarsus whitish. Wings hyaline. Metasoma mostly bright orange, T2-3 somewhat darker anteriorly; T1 mostly light yellow, median 0.5 blackish; T2-4 with posterior yellow stripes.

Female
Unknown.

Comments
The examined specimen is very similar to males of D. tibialis, from which the present species can be differentiated by having T2-4 with posterior yellow stripes (Figs 8C-8D) (vs fully orange, Fig. 15E); anterior transverse carina of propodeum almost straight (Fig. 8B) (vs distinctly arched forwards in the center, Fig. 15F); white band formed by 14 flagellomeres (vs 5-9); scape dorsally pale yellow (vs dark brown, rarely with apical yellow spot); sublateral yellow marks covering most of posterior area of propodeum, the marks close to each other (vs not covering most of posterior area of propodeum, the marks well separated). Also similar to males of D. paratibialis sp. nov., from which it can be readily differentiated by having the metapleuron entirely black (vs with distinct yellow mark); mesosternum black (vs yellow); and crossvein 1cu-a arising slightly basad of 1M+Rs (vs distinctly basad of 1M+Rs).

Distribution records
Peru.

Etymology
From the Greek 'komma', in reference to the sublateral comma-shaped yellow marks on the propodeum.

Male
Unknown.

Comments
Structurally, D. commatus sp. nov. differs from all other species in the genus by having two exclusive features: T1 ventrolateral carina complete but medially almost indistinct; and fore wing crossvein 1cu-a straight but inclivous.

Etymology
From the Anglo-Saxon 'dael', meaning 'valley'; in reference to the deep sternaulus.

Male
The only known male specimen is structurally similar to the female, but the colour pattern differs considerably. Smaller, fore wing 9.2 mm long; antennae missing; T1LW 3.21; T1WW 1.73. Metasoma mostly orange; all femora orange; metapleuron with very small and weak dorso-posterior yellow mark; mesosoma dark brown; hind tibia bright yellow, apically blackish; basal 0.6 of hind t1 orange, apical 0.4 of t1 and t2-5 whitish.

Comments
Structurally, D. daelus sp. nov. differs from all other species in the genus by having two exclusive features: sternaulus deeply impressed, except posterior 0.25 almost indistinct (Fig. 10B-D), and pronotum weakly striate along posterior margin and part of collar, elsewhere rugulose.
Variation. Morphometric ranges for this species can be seen in Table 1. Scape sometimes with a small ventral yellow spot; wrinkling/rugae on pronotum sometimes very weak; pilosity at mesoscutum sometimes scarce at anterior lateral lobes, sometimes dense and uniform; specimen from Guatemala generally more pilose; yellow dash on dorsal margin of pronotum from very short, restricted to anterior region, to almost reaching posterior margin of pronotum; yellow mark at hypoepimeron sometimes connected to main mark at mesopleuron; specimen from Costa Rica with head in a brighter tone of yellow. One specimen from Costa Rica (smallest examined) more pilose than all others, with dark marks on legs and metasoma dark brown instead of black, and marks on T1 less extensive. SUPELETO F.A. et al., Revision of Distictus Townes, 1966 (Hymenoptera, Ichneumonidae) Male Similar to female, most important differences as follows. Fore wing 7.5-9.7 mm; sublateral crests on propodeum weak; wrinkling/rugae on pronotum and mesopleuron weak; anterior transverse carina of propodeum medially very weakly arched forwards; crossvein 1cu-a arising distinctly basad of 1M+Rs. Scape dorsally yellow; mesosternum entirely yellow.

Comments
Structurally, D. mexicanus differs from all other species in the genus by having six exclusive features: mesopleuron mostly finely punctate; supra-clypeal area sparsely pilose and almost impuctate; metapleuron moderately pilose; mesopleural fovea represented only by moderately deep pit; mesoscutum sparsely pilose. Regarding colour, this is the only species in the genus showing a hind femur blackish with ventral face bright yellow (Fig. 11C).

Distribution records
Mexico, Guatemala, Costa Rica.

Etymology
From the Latin 'notabilis', meaning 'notable', in reference to the large size, rich colour pattern and the overall beauty of the species, which draws attention.

Material examined
Total of 1 specimen.
Colour. Head and mesosoma black with yellow marks; metasoma mostly orange. Head black; basal spot on mandible, clypeus except lateral borders and area around median tooth, mouthparts and most of supra-clypeal area light yellow. Supra-clypeal area with oblique blackish marks on ventral 0.3. Orbital band shortly interrupted on malar space, never covering entire width of gena; f6-12 entirely white, f5 and f13 partially white; f13-30 ventrally dark brown. Mesosoma black; collar, dorsal margin of pronotum, central spot on mesoscutum, tegula, scutellum, postscutellum, subalar ridge, central mark on mesopleuron, hypoepimeron, dorsal division of metapleuron, oval mark covering 0.5 of metapleuron and elongate sublateral marks extending from anterior area of propodeum to its posterior apex light yellow. Fore and mid coxae mesally black, laterally yellow; fore and mid first trochanters marked with light yellow and blackish; fore and mid second trochanters marked with light yellow, orange and blackish; fore and mid femur mostly light yellow; fore femur marked with brown and blackish on dorsal and posterior faces; mid femur blackish on anterior and posterior faces; all tibiae deep yellow; fore and mid tarsi basally yellow, blackish towards apex. Hind coxa, trochanters and femur bright orange, coxa with dorso-basal yellow spot and blackish marks on its extreme base; hind tarsus deep yellow. Wings hyaline. Metasoma bright orange; T1 mostly blackish with basal 0.2 and apical 0.25 yellow. Sternites slightly lighter than tergites.

Male
Unknown.

Comments
Structurally, D. notabilis sp. nov. differs from all other species in the genus by having one exclusive feature: pronotum weakly striate along posterior margin and collar, except impunctate elsewhere.
The new species is very similar in colour to D. ateles sp. nov., for which it can be easily mistaken. Distictus notabilis sp. nov. can be differentiated by having the supra-clypeal area ventrally with two oblique blackish marks (vs three blackish marks that almost connect centrally to form an inverted Y in D. ateles sp. nov.); orbital band shortly interrupted, almost meeting at eye margin (Fig. 12A) (vs widely interrupted on malar space, broadly disconnected at eye margin, Fig. 7A); large yellow mark dorsad of spiracle of propodeum (Fig. 12F) (vs very small yellow spot dorsad of spiracle, Fig. 7C); hind coxa with basal dorsal yellow spot not encircled by blackish ring (Fig. 12D) (vs encircled by blackish ring, Fig. 7D); hind femur fully bright orange (vs reddish, apically blackish). The new species is also most similar in structure to D. ateles sp. nov., but differs in 34 features, of which the most important are as follows: epicnemial carina reaching about 0.85 of distance to subalar ridge (vs reaching about 0.70 of distance to subalar ridge); pronotum weakly striate along collar (vs distinctly striate); median tubercle of clypeus small, placed entirely on apical area (vs large, placed mostly on apical area); fore wing crossvein 1cu-a arising a little basad of 1M+Rs (vs distinctly basad of 1M+Rs); spiracle of T1 slightly prominent (vs not prominent); ovipositor slightly downcurved (Fig. 12D) (vs straight, Fig. 7D); apical area of clypeus narrow (vs moderately wide); clypeus basally moderately convex (Fig. 12C) (vs basally nearly flat, Fig. 7D); areolet 0.28 × as high as wide (vs 0.45). The new species is also similar in structure and colour to D. tibialis, but differs by having metapleuron with large yellow mark (Fig. 12D, G) (vs entirely black in D. tibialis, Fig. 15C, G) and anterior area of propodeum with yellow marks (Fig. 12C, F) (vs black, Fig. 15F). Structurally, it differs in 44 features, of which the most important are as follows: posterior area of propodeum strigate (as in Fig. 7C) (vs rugulose, Fig. 15F); mesoscutum densely punctate (vs punctate-coriarious); metapleuron lineaterugulose (vs rugulose); pronotum weakly striate (vs distinctly striate); epicnemial carina reaching about 0.85 of distance to subalar ridge and more or less uniformly curved (vs reaching subalar ridge, irregular); supra-antennal area ventrally distinctly concave (vs ventrally and around ocelli slightly concave); areolet 0.28 × as high as wide (vs 0.31-0.38).

Variation
Morphometric ranges for this species are shown in Table 1. Fore and mid coxae sometimes without dorso-apical brown spots; yellow mark at metapleuron varying a little in size and shape; yellow spot at hypoepimeron varying in size, sometimes covering it almost entirely, sometimes only about half or so; scape dorsally sometimes light brown with yellow spot; vein 3-M sometimes distinctly shorter than 2-M. Two specimens from São Paulo with Cub distinctly convex at apical half; median depression of T1 sometimes very shallow; smaller specimens with supra-clypeal area medially weakly rugulose.

Male
Similar to female, most important differences as follows. Smaller, fore wing 5.7-7.5 mmlong; pronotum polished smooth. Scape dorsally yellow; mesosternum entirely pale yellow; small black mark near base of mandible absent; metasoma with lighter colour than in female; fore and mid coxae pale yellow, without dorso-apical small brown spots.
Variation. Antenna with 28-30 flagellomeres; T1LW 3.01-3.21; T1WW 1.71-1.93. T1 sometimes dorsally dark brown after middle until posterior yellow stripe; yellow mark at metapleuron sometimes small (about half as large as in other specimens); sometimes hind t1 almost entirely blackish; sometimes hind t5 entirely blackish (vs basally whitish and apically blackish in most specimens); sometimes 3-M distinctly shorter or longer than 2-M; rarely scape almost entirely brownish with a very small yellow spot dorso-apically; colour pattern of metasoma varying from orange to light orange; specimen from La Rioja (Argentina) with sublateral yellow marks on posterior area of propodeum connected; two specimens from São Paulo (Brazil) with mesosoma brown (vs black in most specimens).

Comments
Structurally, D. paratibialis sp. nov. differs from all other species in the genus by having four exclusive features: fore wing vein 1-Rs+M with bulla placed near basal 0.3; clypeus at midlength slightly but distictly emarginate; hind wing vein M+Cu apically slightly convex; sulcus between sternaulus and scrobe absent.
This species shares several structural and colour features with D. tibialis. These are the most closely related species of the genus and can be easily confused, but extensive comparisons suggest they are indeed distinct species. They are structurally distinct by 36 features, of which the most important are as follows: posterior area of propodeum strigate-rugulose (Fig. 13B) (vs rugulose in D. tibialis, Fig. 15F); anterior margin of propodeum medially very slightly concave (Fig. 13B) (vs distinctly concave, Fig. 15F); and pronotum weakly striate along posterior margin (vs distinctly striate). The following colour pattern is also distinctive: metapleuron with distinct yellow mark (Fig. 13D) (vs entirely black, Fig. 15C, G); fore and mid coxae with small dorso-apical brown spot (Fig. 13D) (vs fully pale yellow, Fig. 15G); mesosternum with large yellow marks (vs black); large central mark on mesopleuron extending beyond the sternaulus (Fig. 13D) (vs extending to sternaulus, Fig. 15G). SUPELETO F.A. et al., Revision of Distictus Townes, 1966 (Hymenoptera, Ichneumonidae) The new species is also similar to D. ateles sp. nov., but differs in 49 structural features, of which the most important are as follows: posterior area of propodeum strigate-rugulose (Fig. 13B) (vs strigate, Fig. 7C); metapleuron rugulose (vs lineate); mesoscutum punctate-coriarious (vs densely punctate); epicnemial carina irregular and reaching about 0.85 of distance to subalar ridge (vs more or less uniformly curved, reaching about 0.70 of distance to subalar ridge); median tubercle of clypeus very small (vs large); areolet 0.26-0.37 × as high as wide (vs 0.45); ; thyridium about as wide as long (vs distinctly wider than long); propodeum moderately pilose (Fig. 13B) (vs sparsely pilose, Fig. 7C). The new species is also similar in colour pattern, from which it can be isolated by having supra-clypeal area entirely yellow (vs with blackish marks); T1 mostly orange (vs black); hind femur fully reddish-orange (vs reddish, apically blackish); propleuron yellow (vs black).

Distribution records
Brazil (BA, GO, ES, SP), Bolivia, Argentina.  Colour. Head, mesosoma and metasoma reddish-brown and yellow. Head mostly pale yellow; mandible except small basal mark, large spot on malar space and clypeal borders, supra-clypeal area near toruli and ventral portion of supra-antennal area reddish-brown. Dorsal portion of supra-antennal area, vertex, dorsal 0.25 of gena and occiput black. Orbital band covering almost entire width of gena on its ventral 0.7. Flagellum mostly black; f7-9 entirely black, f6 and 10 mostly black, f11 with small basal white mark; f12-30 ventrally dark brown. Mesosoma reddish-brown; small marks on dorsal and ventral portions of collar, dorsal margin of pronotum, central spot on mesoscutum, tegula, scutellum, postscutellum, subalar ridge, large central mark on mesopleuron, anterior portion of hypoepimeron, dorsal division of metapleuron, dorsal mark covering 0.6 of metapleuron and elongate sublateral marks extending from anterior area of propodeum to its posterior apex pale yellow. Median portion of collar and posterior mark on mesoscutum blackish. Fore and mid tibiae mesally reddish, laterally yellow; fore and mid first trochanter dorsally blackish, fore one ventrally yellow; mid one ventrally orange; fore and mid second trochanters and base of femora orange, remainder of femora dorsally blackish, ventrally yellow; all tibiae and hind tarsus pale yellow; fore and mid tarsi basally pale yellow, blackish towards apex. Hind coxa, trochanters and femur reddish-brown, coxa with dorso-basal yellow spot. Wings hyaline. Metasoma reddish-brown, lighter towards posterior segments, T7-8 deep orange; T1 with small marks just dorsad of spiracle, posteriorly with wide yellow stripe. Sternites lighter than tergites.
Variation. Morphometric ranges are shown in Table 1. All examined specimens quite similar to each other, except by the following, slight variations: yellow mark on hypoepimeron sometimes connected to main mesopleural mark, sometimes briefly separated; areolet sometimes distinctly higher than wide, sometimes about as wide as high; one specimen with wrinkling at pronotum and mesopleuron slightly weaker; pronotum sometimes distinctly striate along posterior margin and collar; elongate sublateral yellow marks of propodeum sometimes extending only from posterior margin to anterior tranverse carina; sometimes vein 3-M distinctly shorter than 2-M, rarely longer; sometimes crossvein 1cu-a arising distinctly basad of 1M+Rs; specimen from Ponta Grossa with lateral yellow marks on mesoscutum; two  Townes, 1966 (Hymenoptera, Ichneumonidae) specimens from Nova Teutônia with weak yellow stripe on T1 and with dark marks on tergites; small yellow maks just dorsad of spiracle on T1 in some cases absent or connected with posterior yellow stripe.

Male
Same overall structure and colour pattern as female, but with the following differences. Smaller, fore wing 8.5-11.5 mm long. Antenna with 32 flagellomeres. Supra-clypeal area entirely yellow, without oblique reddish-brown marks; elongate sublateral yellow marks of propodeum extending from posterior margin to anterior tranverse carina; labial and maxillary palpus pale yellow, brownish towards apex; spiracle of T1 prominent; collar entirely yellow, without interruptions; anterior tranverse carina of propodeum slightly arched forwards, in two cases practically straight; small yellow marks just dorsad of spiracle on T1 absent.
Variation. As with the female, males show relatively stable structure and colour patterns. Small variations which might be of some interest are as follows: T1LW 2.62-2.94; T1WW 1.80-2.03. Specimen from Pelotas (RS) with areolet distinctly higher than wide; posterior yellow stripe on T1 sometimes almost indistinct; tergites sometimes with blackish marks; smaller specimen with pronotum polished smooth.

Comments
The new species differs from all other species in the genus by having the mesosoma reddish-brown with yellow marks (Fig. 14C, E) (vs mesosoma black with yellow marks, Figs 9C, 15G). It is also the only species of Distictus with the orbital band interrupted on the temple (Fig. 14E).
Although very different in colour, D. terrosus sp. nov. is most similar in structure to D. mexicanus, from which it differs in 49 features, of which the most important are as follows: fore wing crossvein 1m-cu continuous with vein 1-Rs+M (vs limit between these two veins clearly traceable); fore wing crossvein 1m-cu more or less uniformly curved (vs irregular); anterior transverse carina of propodeum laterally approximately straight, medially distinctly arched forwards (vs slightly arched forwards, medially more distinctly curved); mesopleuron posteriorly distinctly lineate (vs on dorsal posterior corner distinctly lineate); epicnemial carina reaching about 0.85 of distance to subalar ridge (vs almost reaching subalar ridge); fore wing vein 3r-m about as long as 2r-m (vs distinctly shorter than 2r-m); anterior margin of propodeum medially very slightly concave (vs concave); supra-antennal area ventrally distinctly concave (vs ventrally very slightly concave); apical area of clypeus moderately wide (vs narrow); median depression of T1 very shallow (vs absent); sulcus between sternaulus and scrobe almost indistinct (vs distinct); mandible densely pilose (vs sparsely pilose); metapleuron densely pilose (vs moderately pilose).

Distictus tibialis
Variation. Morphometric ranges for this species can be seen in Table 1. Mesosternum centrally densely pilose; supra-clypeal area sometimes entirely yellow, or sometimes with small blackish spots, or sometimes M-shaped spot; malar space rarely yellow (smaller specimens); orbital band sometimes complete, but very narrow on malar space; supra-antennal area medially and near ocelli sometimes rugulose; clypeus sometimes basally slightly convex; T1 posteriorly usually with a wide yellow band, covering about 10% of its length, but in some specimens this band fading or smaller to different degrees, up to entirely absent; metasoma sometimes darker (probably related to specimen conservation); yellow spot on hypoepimeron varying in size; yellow spot on mesopleuron varying in size and shape; veins 2Cua and 2cu-a sometimes aligned straight, sometimes evenly arched; vein Cub sometimes straight to distinctly curved on posterior portion; areolet rarely higher than wide; crossvein 1cu-a sometimes arising a little basad of 1M+Rs; vein 3-M sometimes distinctly longer than 2-M; median depression of T1 sometimes absent; lateral depression of T1 absent or very shallow in smaller specimens; yellow mark on propleuron varying in size and shape, sometimes propleuron fully yellow or sometimes almost entirely black; anterior side of metapleuron sometimes very densely pilose.

Male
Face never black, except malar space; T1 with fuscous lateral areas; areolet usually slightly less convergent than in female.

Types
The original type specimen is lost (Yu et al. 2005) and this is problematic because this is, at the same time, the type species, the most common species of the genus, and a complex taxon, easy to confuse with other species, the most obvious of which is D. paratibialis sp. nov. The designation of a neotype is necessary to settle and stabilize the definition of the species. Brullé (1846: 242) cites the original location of the type specimen as "Brésil (prov. de Guaratuba)", which corresponds to the present city of Guaratuba, state of Paraná, in southern Brazil. We have not been able to find specimens of Distictus from Guaratuba. The present designation of a neotype is justified on the basis of its representativeness of the species, as interpreted here, the specimen's integrity, and because the collecting place was the closest possible (80 km) to Guaratuba.

Comments
Structurally, D. tibialis differs from all other species in the genus by having four exclusive features: posterior area of propodeum rugulose (Fig. 15F); epicnemial carina reaching subalar ridge; pronotum distinctly striate along posterior margin and collar; and epomia distinctly sinuous after diverging from pronotal collar.
European Journal of Taxonomy 542: 1-64 (2019) This species shares several structural and colour features with D. paratibialis sp. nov. These are the most similar species in Distictus and can be easily confused. They are nonetheless structurally distinct by 36 features, of which the most important are as follows: posterior area of propodeum rugulose (Fig. 15F) (vs strigate-rugulose in D. paratibialis sp. nov., Fig. 13B); anterior margin of propodeum medially distinctly concave (Fig. 15F) (vs medially very slightly concave, Fig. 13B); pronotum distinctly striate along posterior margin (vs weakly striate). The new species also differs in colour pattern by having metapleuron entirely black (Fig. 15C) (vs with distinct yellow mark, Fig. 13D); fore and mid coxae entirely pale yellow (Fig. 15G) (vs with small dorso-apical brown spot, Fig. 13D); mesosternum black (vs with large yellow marks); and large central mark on mesopleuron extending to sternaulus (Fig. 15G) (vs extending beyond sternaulus, Fig. 13D).
The new species is also similar to D. ateles sp. nov., from which it differs in 50 structural features, of which the most important are as follows: posterior area of propodeum rugulose and matte ( propodeum moderately pilose (vs sparsely pilose). The two species are also similar in colour pattern, but D. tibialis can be isolated by having the metapleuron entirely black (Fig. 15G) (vs with distinct yellow mark, Fig. 7D); T1 orange (vs mostly black); hind femur fully reddish (Fig. 15G) (vs apically blackish, Fig. 7D).

Host
One specimen (USUC 143.2) was reared from Diatraea saccharalis (Fabricius, 1794) (Lepidoptera, Crambidae), the sugarcane borer. This moth is the most important pest of sugarcane, and some parasitoid species have been successfully used in its biological control in Brazil (see Molnár et al. 2016 Parker et al. 1953). The reared specimen apparently died inside its pupa, or soon after emerging: wings are delicate and collapsed, propodeum apex is damaged and ovipositor valves separated.

Discussion
This is the most complete investigation of Distictus up to now, supported by the study of 289 specimens and 100 morphological characters, of which 23 are morphometric ratios, generated from over 2200 measurements. It seems noteworthy that, even after such a thorough investigation and genus-level redefinition, the concept of Distictus as proposed by Townes (1966Townes ( , 1970 was essentially correct. This might be somewhat surprising because Distictus is not easy to recognise as a separate, distinct unit, the main problem being its overall similarity with other Cryptinae genera, such as Mallochia, Cyclaulus, Digonocryptus and others. Townes (1970) also had a fair notion of the moderate diversity of Distictus, reporting only 5 species (4 undescribed). In fact, the group does not appear to be speciose, with only twelve species reported here. In addition, based mainly on the number of examined specimens and the SUPELETO F. A. et al., Revision of Distictus Townes, 1966 (Hymenoptera, Ichneumonidae) most recent date of collection, only D. tibialis can be considered common, while all other Distictus can be classified as moderately common to uncommon (D. ateles sp. nov., D. mexicanus, D. paratibialis sp. nov., D. terrosus sp. nov.), or rare (D. apaensis sp. nov., D. ardens sp. nov., D. asterios sp. nov., D. daelus sp. nov., D. caligaris sp. nov., D. commatus sp. nov., D. notabilis sp. nov.).
In spite of the inclusion of Distictus in a morphological (Aguiar 2005a, using literature information) and in a morphological + molecular (Santos 2017, using D. tibialis) phylogenetic investigation, its precise relationships with other Cryptinae remain to be settled. The evolutionary relationships and biogeographic history of its species also need to be investigated.
Brazil) helped with nomenclatural questions. We are also grateful to the editors, Gavin Broad, Danny Eibye-Jacobsen and Kristiaan Hoedemakers, who greatly contributed for the accuracy of the final work, providing a thorough and attentive review. The Ernst Mayr (Museum of Comparative Zoology, Harvard University), mini-ARTS (Society of Systematic Biologists) and CanaColl (Agriculture Canada) grants funded visits to the Townes collection (then at the American Entomological Institute in Gainesville) and CNCI. Research funding was initially provided by Fundação de Amparo à Pesquisa do Espírito Santo/ FAPES (Process 45.440.611/2009), and Conselho Nacional de Pesquisas/CNPq (Process 480507/2010-4), Brazil, to APA. BFS is currently supported by a Global Genome Initiative Buck Postdoctoral Fellowship.