The genus may be distinguished by the following combination of characters: cephalic process conical, strongly curved upward, and gradually narrowing apicad; vertex with posterior plane elevated above pronotum, wider (e.g., at posterior margin) than transverse diameter of eyes in dorsal view, lateral carinae abruptly constricted and curved upward in front of eyes, converging anteriad, apical margin broadly angulately convex to nearly straight; frons flat, lateral, intermediate and median carinae weakly ridged, lateral carinae nearly parallel in most of their length, gradually converging apicad in front of eyes; pronotum with intermediate carinae ridged and nearly reaching posterior margin, upper lateral carina greenly thickened (not continued on the tegula), posterior margin angularly concave, not notched; mesonotum with lateral carinae incurved anteriad, reaching and connecting median carina; tegulae lacking carina; tegmina macropterous, veins setose on ventral surface, nodal line present, ScP+R+MP long, MP₁₊₂, MP₃₊₄ and CuA₁ forked near nodal line (near midlength), the longest folding line between MP₃ and MP₄; fore femora without spines, hind tibiae with eight apical teeth; endosomal processes sclerotised apically; phallobase with pairs of large and stout spines.

General colour of body pale green to stramineous green, marked with green, ochraceous and black on head and thorax (Figs 1, 2).

Head. Head (Figs 3A–C, 4A–C, 6A–C, 7A–C) in front of eyes produced into a short cephalic process. Cephalic process conical, strongly curved upward, and gradually narrowing toward apex. Vertex (Figs 3A, 4A, 6A, 7A) with posterior plane elevated above pronotum, wider than transverse diameter of eyes in dorsal view (Figs 3A, 4A, 6A, 7A); lateral carinae keeled, gradually converging (with a lateral inflection anterior to eyes), abruptly constricted and curved upward in front of eyes, and then converging anteriad, in lateral view (Figs 3B, 4B, 6B, 7B), the process bent upward at approximately 60–90° (sometimes more than 90°) in front of eyes; median carina indistinct, somewhat depressed medially, or weakly ridged posteriorly; apical margin broadly angularly convex to nearly straight, not acuminate at apex, posterior margin ridged and broadly and angularly concave, concavity projecting distinctly beyond middle of eyes. Frons (Figs 3C, 4C, 6C, 7C) flat, elongate and relatively broad; lateral carinae weakly ridged, slightly expanded outward below antennae, nearly parallel in most of their length, gradually converging apicad in front of eyes; intermediate carinae weekly keeled, nearly reaching frontoclypeal suture; median carina complete but obscure. Frontoclypeal suture arched. Postclypeus and anteclypeus (Figs 3C, 4C, 6C, 7C) cuneate, slightly convex medially; lateral and median carinae keeled. Rostrum long, second segment slightly longer than third segment, surpassing middle coxae, third segment reaching middle of hind femora. Compound eyes large and rounded, callus postocularis forming a triangular process protruded posteriad. Antenna with very small scape; pedicel subglobose, with more than 50 sensory plaque organs distributed over entire surface; flagellum long, setuliform.

Thorax. Pronotum (Figs 3A, 4A, 6A, 7A) distinctly shorter than mesonotum medially, narrow anteriorly, broad posteriorly; anterior margin arcuately convex medially, lateral marginal areas convex and sloping with two long longitudinal carinae on each side between eyes and tegulae, upper lateral carina greenly thickened (not continued on the tegula); in dorsal view (Figs 3A, 4A, 6A, 7A), lower lateral carinae expanded just behind eyes; posterior margin angularly concave, not notched; median carina distinct, with a deep lateral pit at side; intermediate carinae keeled and nearly complete. Mesonotum (Figs 3A, 4A, 6A, 7A) distinctly tricarinate, lateral carinae incurved anteriad, reaching median carina. Tegulae lacking carina.

Tegmina (Figs 2G, H) membranous, hyaline, and macropterous, extending far beyond the tip of abdomen; veins setose on ventral surface; transverse veinlets r-m, imp and mp-cu connecting some short segments of veins RP, MP and CuA to form nodal line; ScP+R+MP long, much longer than basal cell; ScP+R forked in distal 3/5; MP bifurcating MP₁₊₂ and MP₃₊₄ (forming cell C3) near midlength, MP₁₊₂ and MP₃₊₄ forked near level of bifurcation of ScP+R, near nodal line, MP₁, MP₂, MP₃ and MP₄ each forked at apex; CuA forked before bifurcation of MP (forming C5 cell), CuA₁ bifurcating CuA_1a and CuA_1b before mp-cu, near nodal line; mp-cu connecting MP₃₊₄ and CuA_1a (forming C4 cell); Pcu and A1 fused in proximal third of clavus, composite vein reaching wing margin before claval apex (not reaching CuP); numbers of apical cells of RP, MP and CuA 3, 7, 3–4, respectively; pterostigmal area elongate, with three cells; folding lines present, the longest one between MP₃ and MP₄.

Hindwings with ScP+R+MP short, about a half of basal cell; ScP+RA and RP forked near apical one third; MP bifurcating MP₁₊₂ and MP₃₊₄ little posterior to ScP+RA and CuA; CuA bifurcating CuA₁ and CuA₂ much anterior to ScP+RA and MP, CuA₁ four-branched distally, and CuA₂ not branched; transverse veinlets r–m and mp-cu slightly posterior to bifurcation of MP.

Legs long; fore femora elongate, not flattened and dilated, without spines; fore and middle tarsomeres I and II with more than two acutellae; hind tibiae distinctly elongate, nearly twice as long as hind femora, with four lateral spines and eight apical teeth; hind tarsomeres I and II with about 7–9 and 8–9 apical teeth, respectively.

Male genitalia. Pygofer, in lateral view (Figs 3E, 4E, 6E, 7E), irregularly quadrate to pentagonal, distinctly wider ventrally than dorsally, dorsal margin slightly excavated to accommodate segment X, dorsoposterior margins angular. Gonostyles (Figs 3F, 4F, 6F, 7F) symmetrical, in lateral view (Figs 3G, 4G, 6G, 7G) broad, base narrow, expanded distally, broadest in middle, and then tapering posteriad, apex rounded; dorsal margin with a claw-like, apically sclerotised process (dorsal process), directed dorsad, outer dorsal edge with a hook-like process near middle, directed ventrad. Aedeagus (Figs 3H–J, 4H–J, 6H–J, 7H–J) with a pair of endosomal processes extended from phallotheca and curved dorsoanteriad or laterad; these processes mostly membranous, sclerotised apically, tapering posteriad to form large and stout spines; phallobase sclerotised basally and membranous and inflated apically, with paired lobes with large and stout spines. Segment X long oval, in lateral view (Figs 3E, 4E, 6E, 7E), ventral margin gradually widening from base to apex; in dorsal view (Figs 3D, 4D, 6D, 7D), with apex excavated to accommodate anal style; anal style elongate and large, beyond apical ventral margin of segment X.

Female genitalia. Gonocoxae VIII (Fig. 5D) with a membranous and flattened endogonocoxal processes (Gxp), bearing tiny setae on apex. Gonapophyses VIII (Fig. 5D) with anterior connective lamina large and sclerotized, with seven teeth of varying sizes and shapes. Gonapophyses IX (Fig. 5E, F) with posterior connective lamina triangular, symmetrical, weakly bifurcated at apex, fused with the intergonocoxal plate at base. Gonoplacs (Fig. 5G, H) with two lobes homologous, first lobe (lateral lobe) axe-shaped, sclerotized, large and elongate, apical margin filmy and truncate, with cluster of long setae on apex (no sensory appendage, viz. Igava spp.); second lobe (posterior lobe) large, broad basally and tapering posteriad, the edge membranous containing long sclerotized plate. Segment X (Fig. 5A) trapeziform, large and broad in dorsal view, apex deeply excavated to accommodate anal style; anal style small.

Trigava is revised here to contain four species including two new species. The species of the genus are distributed in the northwest of South America and were recorded from Peru, Bolivia and Brazil, as far as known (Fig. 8).

In addition to the diagnostic characters listed by O’Brien (1999), Trigava may be separated from Igava Melichar by characters diagnostic at the tribal level, such as on the tegmen and the female genitalia (Song et al. 2018). For example, the second postnodal line of the tegmen and the apical sensory appendage of gonoplacs I are absent in Trigava, but they are present in Igava.

In the tribe Nersiini, Trigava is externally similar to the genus Nersia Stål, 1862, but can be distinguished from the latter by the head strongly curved upward (slightly curved upward in Nersia); the median carina of vertex absent (present in Nersia), and the tegulae lacking carina (present in Nersia). See also the Discussion.

Peru, Department of Cuzco, Quispicanchi Province, Marcapata.

Measurements (in mm; 3♂, 1♀). Body length from apex of head to tip of tegmina: ♂ 10.8–11.1, ♀ 11.7; head length (includes: apex of cephalic process to constricted and curved part + from curved part to base of eyes): ♂♀ (0.2–0.3)+(0.6–0.7); head width including eyes: ♂ 1.4–1.5, ♀ 1.6; tegmen length: ♂ 9.0–9.3, ♀ 9.6.

Coloration. Head stramineous green, apical spot between intermediate carinae of frons black, intermediate carinae of frons reddish brown, lateral areas of head green. Pronotum and mesonotum stramineous green, upper lateral carinae of pronotum green. Tegmina and hindwings membrane hyaline, veins green to greenish yellow, pterostigmal area more or less greenish ochraceous. Legs yellowish brown, base, apex and apical spines of tibiae fuscous. Abdomen dorsally and ventrally greenish ochraceous.

Structure. Head with cephalic process very short, in lateral view (Fig. 3B), strongly curved upward about 90° (or more than 90° in lectotype, Fig. 2A) in front of eyes. Vertex (Fig. 3A) broad, with ratio of length at midline to width between eyes (0.9–1.0):1. Frons (Fig. 3C) flat, relatively broad, with ratio of length at midline to maximum width 2.0:1, intermediate and median carinae obscure.

Male genitalia. Pygofer in lateral view (Fig. 3E) with ratio of ventral to dorsal width about 2.5:1; posterior margin produced angulately near middle. Gonostyles (Fig. 3F) large and broad, dorsal process short, acute apically, more or less incurved and directed dorsoanteriad; hook-like process situated submedially, distinctly elevated above dorsal process, curved basad (Fig. 3G). Aedeagus (Fig. 3H–J) elongate, endosomal processes curved dorsoanteriad; phallobase sclerotized and pigmented at lateral sides, membranous and slightly inflated dorsally and ventrally: dorsal lobes V-shaped at apex, directed posteriad; a pair of lateral lobes large and elongate, base conical, directed anterolaterad, mostly tapering apicad, apex with a large long spine, directed posteriad; ventral lobes small, butterfly-shaped, base expanded laterad, with a minute tooth, apex produced in a pair of short and stout lobes, without spine, directed laterad. Segment X (Fig. 3D, E), in dorsal view, lateral margins more or less convex near middle, with ratio of length to width near middle about 2.0:1.

Female genitalia. As in generic description.

Lectotype (here designated), ♂, (1) “Peru, Marcapata”; (2) “Enh. brachycephala [Melichar’s handwriting], det. Melichar”; (3) “Typus” [dark red label]; (4) “Collectio Dr. L. Melichar, Moravské museum Brno”; (5) “Syntypus, Igava brachycephala sp.n. Melichar, 1912, ♂ [P. Lauterer’s handwriting], P. Lauterer det. 1991”; (7) “Syn- typus” [red label]; (7) “Invent. č. 4941/Ent., Mor. muzeum, Brno”; (8) “Trigava brachycephala [Zhi-Shun Song’s handwriting] det. Z.S. Song 2014”; (9) “Lectotypus ♂, Igava brachycephala Melichar, 1912, designated by Z.S. Song & I. Malenovský, 2023” [newly added red label] (MMBC; dry-mounted, glued on a rectangular card label, abdomen detached, macerated, preserved in glycerol and enclosed in a glass microvial placed on the same pin as the specimen). Paralectotype, 1♂, (1) “Peru S, Marcapata, Garlepp c.”; (2) “Coll. A. Jacobi, 1912 – 3” [green label]; (3) “brachycephala” [handwriting]; (4) “Igava Mel.” [handwriting]; (5) “Paralectotypus ♂, Igava brachycephala Melichar, 1912, labelled by I. Malenovský, 2023” [newly added red label] (MTD).

Peru: 1♂, “Peru, S.V. Garlepp”; “Igava brachycephala Mel. [H. Synave’s handwriting], H. Synave det., 1969” (MFNB); 1♂, 1♀, “Peru” (MTD).

Southeastern Peru.

Melichar (1912) described Igava brachycephala Melichar based on material from “Peru, Marcapata (Garlepp) (Mus. Budapest, Dresden)”. He did not state the number of the specimens he used for the description nor did he designate a holotype. One of his syntypes has been preserved in Melichar’s personal collection in MMBC and we used this male specimen for the redescription of the species. According to Article 74 of ICZN (1999), we designate the specimen in MMBC as the lectotype for I. brachycephala to stabilize the nomenclature. Another conspecific male with collecting data fully matching the original description has been located by us in MTD and was labelled by us as a paralectotype.

Brazil, Rondônia State, 62 km SW Ariquemes, Fazenda, Rancho Grande.

Holotype ♂, Brazil: Rondônia, 62 km, SW Ariquemes, Fzda, Rancho Grande, 19-XI-1994, C.W. O’Brien & L.B. O’Brien leg. (LBOB; dry-mounted, pinned). Paratypes: Brazil: 1♂, 1♀, same data as holotype but 18-XI-1994 (LBOB); 1♂, same data as holotype but 4–16-XI-1997, J.E. Eger leg. (LBOB).

Trigava obrieni sp. nov. is similar to T. brachycephala in most characters, but can be separated from the latter by the longer head curved upward about 60° in front of eyes (in T. brachycephala, the cephalic process is distinctly shorter and curved upward more than 90° in front of eyes) and the ventral lobes of the aedeagus without a tooth at the base (with a minute tooth at base in T. brachycephala). This new species also may be differentiated from T. recurva (Melichar) by the gonostyles with the dorsal process short and the hook-like process situated submedially and curved basad (dorsal process distinctly elongate, hook-like process situated more basally and curved apicad in T. recurva), and the ventral lobes of the aedeagus without long spines (with long spines in T. recurva).

Measurements (in mm; 3♂, 1♀). Body length from apex of head to tip of tegmina: ♂ 10.8–11.2, ♀ 12.5; head length (includes: apex of cephalic process to constricted and curved part + from curved part to base of eyes): ♂♀ (0.4–0.5)+(1.0–1.1); head width including eyes: ♂ 1.4–1.5, ♀ 1.6; tegmen length: ♂ 8.5–8.9, ♀ 9.8.

Coloration. Head stramineous green, lateral and intermediate carinae of frons in front of eyes black to blackish brown, lateral areas in front of eyes green. Pronotum and mesonotum stramineous green, upper lateral carinae of pronotum green. Tegmina and hindwings with membrane hyaline, costal margin black to dark brown, veins green to greenish yellow, pterostigmal area more or less greenish ochraceous. Legs yellowish brown, base, apex and apical spines of tibiae fuscous. Abdomen dorsally and ventrally greenish ochraceous.

Structure. Head with cephalic process relatively long, in lateral view (Fig. 4B), curved upward about 60° in front of eyes. Vertex (Fig. 4A) broad, with ratio of length at midline to width between eyes (1.5–1.6):1. Frons (Fig. 4C) flat, relatively broad, with ratio of length at midline to maximum width 2.4:1.

Male genitalia. Pygofer in lateral view (Fig. 4E) with ratio of ventral to dorsal width about 1.7:1; posterior margin produced into a small, apically obtuse process near middle. Gonostyles (Fig. 4F) large and broad, dorsal process short, acute apically, more or less incurved and directed dorsoanteriad; hook-like process placed submedially, horizontal with dorsal process, curved basad (Fig. 4G). Aedeagus (Fig. 4H–J) slender and elongate, endosomal processes curved dorsoanteriad; phallobase sclerotized and pigmented at lateral sides, membranous and slightly inflated dorsally and ventrally: dorsal lobes V-shaped at apex, curved and directed posterolaterad; a pair of lateral lobes large and elongate, thumb-like, apex with a long spine, directed posteriad; ventral lobe small, butterfly-shaped, base expanded laterad, apex produced in a pair of thumb-like moderate lobes, without spine, directed laterad. Segment X (Fig. 4D, E), in dorsal view, with lateral margins more or less convex near middle, with ratio of length to width near middle about 2.0:1.

Female genitalia. As in generic description (Fig. 5A–H).

The new species is named after the late Dr Charlie W. O’Brien, former professor at Florida Agricultural and Mechanical University, USA, one of the world’s top experts in weevils, collector of the type specimens and husband of Dr Lois B. O’Brien, in recognition of their kindest help and support to the first author when he visited USA in 2017. The species name is to be treated as a noun in genitive case.

Northwestern Brazil.

Peru, Department of Cuzco, Cosñipata Valley.

Holotype ♂, Peru: “Peru, Dep Cuzco, Cosnipata-Ebene, 1000 m, XI-XII-[19]00, S.V. Garlepp leg.” (MFNB; dry-mounted, pinned).

Trigava peruensis sp. nov. is externally similar to T. brachycephala, but can be separated from the latter by the gonostyles with the dorsal process elongate and the hook-like process placed more basally and curved apicad (dorsal process short and hook-like process placed submedially and curved basad in T. brachycephala), and the ventral lobes of the aedeagus with long spines (without long spines in T. brachycephala). It can be distinguished from T. recurva by the shorter cephalic process curved upward about 90° in front of the eyes (the longer head curved upward about 60° in front of eyes in T. recurva) and the ventral lobes of the aedeagus weakly trilobed (nearly cross-shaped in T. recurva).

Measurements (in mm; 1♂). Body length from apex of head to tip of tegmina: 11.7; head length (includes: apex of cephalic process to constricted and curved part + from curved part to base of eyes): 0.3+1.1; head width including eyes: 1.6; tegmen length: 9.7.

Coloration. Head stramineous green, lateral carinae of vertex and frons reddish brown, intermediate carinae of frons in front of eyes black to reddish brown, lateral areas in front of eyes green. Pronotum and mesonotum stramineous green, upper lateral carinae of pronotum green. Tegmina and hindwings with membrane hyaline, costal margin dark brown, veins green to greenish yellow, pterostigmal area greenish ochraceous. Legs yellowish brown, base, apex and apical spines of tibiae fuscous. Abdomen dorsally and ventrally greenish ochraceous.

Structure. Head with cephalic process short, in lateral view (Fig. 6B), curved upward nearly 90° in front of eyes. Vertex (Fig. 6A) broad, with ratio of length at midline to width between eyes (1.1–1.2):1. Frons (Fig. 6C) flat, relatively broad, with ratio of length at midline to maximum width 2.2:1, intermediate and median carinae obscure.

Male genitalia. Pygofer in lateral view (Fig. 6E) with ratio of ventral to dorsal width about 2.0:1; posterior margin produced angulately near middle. Gonostyles (Fig. 6F) large and broad, dorsal process elongate, triangular, acute apically, more or less incurved and directed dorsoanteriad; hook-like process placed sub-basally, below dorsal process, curved apicad (Fig. 6G). Aedeagus (Fig. 6H–J) large and stout, endosomal processes curved dorsoanteriad; phallobase sclerotized and pigmented at lateral sides, membranous and slightly inflated dorsally and ventrally: dorsal lobes small, V-shaped at apex, directed posteriad; a pair of lateral lobes large and elongate, thumb-like, tapering apicad, apex with a large long spine, directed posterolaterad; ventral lobes large, weakly trilobed, base protruded laterad, with a large long spine, apex produced in a long triangular lobe, without spine, directed posteriad. Segment X (Fig. 6D, E), in dorsal view, with lateral margins more or less convex near middle, with ratio of length to width near middle about 2.1:1.

Female. Unknown.

The new species is named for its occurrence in Peru. The specific epithet ‘peruensis’ is to be treated as a Latinized adjective in nominative singular.

Southeastern Peru.

Bolivia, La Paz Department, Mapiri.

Measurements (in mm; 1♂, 1♀). Body length from apex of head to tip of tegmina: ♂ 13.8, ♀ 14.1; head length (includes: apex of cephalic process to constricted and curved part + from curved part to base of eyes): ♂♀ 0.6+(0.9–1.0); head width including eyes: ♂ 1.7, ♀ 1.6; tegmen length: ♂ 11.4, ♀ 11.7.

Coloration. Head stramineous green, lateral carinae of vertex reddish brown, lateral and intermediate carinae of frons in front of eyes black to reddish brown, lateral areas in front of eyes green. Pronotum and mesonotum stramineous green, upper lateral carinae of pronotum green. Tegmina and hindwings with membrane hyaline, costal margin black to dark brown, veins green to greenish yellow, pterostigmal area more or less greenish ochraceous. Legs yellowish brown, base, apex and apical spines of tibiae fuscous. Abdomen dorsally and ventrally greenish ochraceous.

Structure. Head with cephalic process relatively long, in lateral view (Fig. 7B), curved upward about 60° in front of eyes. Vertex (Fig. 7A) broad, with ratio of length at midline to width between eyes (1.6–1.7):1. Frons (Fig. 7C) flat, relatively broad, with ratio of length at midline to maximum width 2.6:1.

Male genitalia. Pygofer in lateral view (Fig. 7E) with ratio of ventral to dorsal width about 2.1:1; posterior margin broadly angular near middle. Gonostyles (Fig. 7F) large and broad, dorsal process elongate, triangular, acute apically, more or less incurved and directed dorsoanteriad; hook-like process situated sub-basally, slightly below dorsal process, curved apicad (Fig. 7G). Aedeagus (Fig. 7H–J) large and stout, endosomal processes curved dorsoanteriad; phallobase sclerotized and pigmented at lateral sides, membranous and slightly inflated dorsally and ventrally: dorsal lobes small, U-shaped at apex, directed posteriad; a pair of lateral lobes large and elongate, base rounded and expanded laterad, remaining thumb-like, subapex with a large long spine, directed posteriad; ventral lobes large, nearly cross-shaped in ventral view (Fig. 7J), base protruded anteriad, middle expanded laterad, with a large and stout spine, apex produced in a large thumb-like lobe, without spine, directed posteriad. Segment X (Fig. 7D, E), in dorsal view, lateral margins more or less convex near middle, with ratio of length to width near middle about 1.8:1.

Female genitalia. As in generic description.

Lectotype (here designated), ♂, (1) “Bolivia, Mapiri”; (2) “recurva [Melichar’s handwriting], det. Melichar”; (3) “Typus” [dark red label]; (4) “Collectio Dr. L. Melichar, Moravské museum Brno”; (5) “Syntypus, Igava recurva sp.n. Melichar, 1912, ♂ [P. Lauterer’s handwriting], P. Lauterer det 1991”; (6) “Syn- typus” [red label]; (7) “Invent. č. 4942/Ent., Mor. muzeum, Brno”; (8) “Trigava recurva (Melichar) [Zhi-Shun Song’s handwriting] det. Z.S. Song 2014”; (9) “Lectotypus ♂, Igava recurva Melichar, 1912, desig. by Z. S. Song & I. Malenovský, 2023” [newly added red label] (MMBC). Paralectotype, 1♀, (1) “Bolivia N, Yungas, Garlepp c.”; (2) “Coll. A. Jacobi, 1912 – 3” [green label]; (3) “Enhydria recurva M” [handwriting]; (4) “Paralectotypus ♀, Igava recurva Melichar, 1912, labelled by I. Malenovský, 2023” [newly added red label] (MTD).

Northwestern Bolivia, southern Peru (Melichar 1912).

Igava recurva Melichar was described based on an unspecified number of specimens from “Peru, Pachitea, Marcapata; Bolivien, Mapiri, Yungas (Garlepp) (Mus. Budapest und Dresden)” (Melichar 1912). One male syntype from Bolivia, Mapiri preserved in Melichar’s personal collection in MMBC is here used for the redescription of the species and designated as the lectotype according to Article 74 of ICZN (1999) to stabilize the nomenclature. Another conspecific female from Bolivia with collecting data matching the original description has been located by us in MTD and was labelled as a paralectotype. Specimens from Peru have not been examined by us.