Labilochus brevipalpis Khalaim & Ruíz-Cancino, sp. n.

The new genus contains only the type species, L. brevipalpis, described below.

The genus is immediately recognisable by its extremely long glossa and galeae (Fig. 2) and reduced number of segments of the maxillary and labial palps. This is the only genus in the subfamily (and probably in the family) having such long glossa and galeae in combination with very short palps. Some taxa of Tersilochinae (e.g. genera Heterocola Förster and Palpator Khalaim, some species of Gonolochus Förster) possess long mouthparts including palps (especially maxillary palp), but none has the long glossa and galeae AND short palps in combination. The formula of maxillary and labial palps (3:2) is also unique within the subfamily; normally tersilochine species have 4-segmented maxillary and 3-segmented labial palps. The new genus is also distinct by having the head almost straight behind the eyes in dorsal view and the occipital carina lacking laterally.

Labilochus belongs to the Tersilochus group of genera, having a right-angled radial cell (Fig. 3) and the first metasomal segment with a distinct glymma joining by a deep furrow to the ventral part of the postpetiole. Within this group, Labilochus is most similar to the genus Probles Förster as it has a well-developed foveate groove on the mesopleuron (Fig. 5) and a long thyridial depression (Fig. 6).

Head in dorsal view almost straight, weakly tapered behind eyes (Fig. 4); temple 0.9 times as long as eye width. Mandible with upper tooth much longer than lower tooth. Clypeus broad, lenticular, almost flat in lateral view, separated from face by weak furrow. Glossa and galeae very long, thin, equal in length, reaching past posterior end of hind coxa (Fig. 2); glossa not forked; maxillary palp 3-segmented, labial palp 2-segmented, both are very short (Fig. 2). Malar space 0.8 times as long as basal mandibular width in female and 0.5 times in male. Antennal flagellum slightly tapered towards apex, with 21–22 flagellomeres (Fig. 1). Occipital carina present dorsally and ventrally (next to mandibular base), absent laterally. Hypostomal carina absent.

Notaulus weakly impressed, without wrinkles. Scutellum with lateral longitudinal carinae developed in its anterior 0.3–0.4 (Fig. 4). Foveate groove deep, sharp, with strong transverse wrinkles, strongly oblique, curved, not reaching epicnemial carina anteriorly (Fig. 5). Propodeum (Fig. 6) with transverse carina well developed, complete; basal area strongly impressed, elongate, distinctly widened anteriorly, 0.35 times as long as apical area, with basal longitudinal carinae indistinct. Propodeal spiracle separated from pleural carina by about 1.5 times diameter of spiracle. Apical area flat, pointed anteriorly; apical longitudinal carinae reaching transverse carina anteriorly, distinct posteriorly and rather weak anteriorly.

Fore wing (Fig. 3) with first and second abscissae of radius (Rs+2r and Rs) meeting at right angle; both abscissae straight. Intercubitus and abscissa of cubitus between intercubitus and second recurrent vein (abscissa of M between 2rs-m and 2m-cu) not or weakly thickened. Metacarpus (R1) not reaching apex of wing. Hind wing with nervellus (cu1&cu-a) vertical. Legs slender. Hind femur 4.6 times as long as broad and almost 0.85 times as long as tibia. Hind basitarsus 0.45 times as long as tibia (Fig. 2).

First tergite slender, postpetiole clearly separated from petiole (Fig. 6). Glymma distinct, situated in apical 0.6 of tergite, joining by distinct furrow to ventral part of postpetiole. Thyridial depression deep, about 2.5 times as long as broad (Fig. 6). Ovipositor long, evenly upcurved, slender, with very weak dorsal subapical depression; sheath about 3.5 times as long as first tergite.

Named after its extremely long labium. Gender masculine.

Female. Body length 4.0 mm. Fore wing length 2.9 mm.

Clypeus smooth, with very fine punctures in upper part. Antennal flagellum with 21 flagellomeres (Fig. 1); all flagellomeres (except basal and apical ones) more or less equally elongate, about 1.2–1.3 times as long as broad; flagellomeres 4 to 6 with subapical finger-shaped structures on outer surface. Face, frons and vertex with very fine, inconspicuous, dense punctures on smooth and weakly shining background. Temple polished, impunctate. Mesoscutum very finely punctate on smooth and weakly shining background. Mesopleuron mostly polished and impunctate. Foveate groove postero-ventrally covered by glue and indiscernible. Propodeum weakly shining, impunctate. Fore wing with intercubitus (2rs-m) somewhat longer than abscissa of cubitus between intercubitus and second recurrent vein (abscissa of M between 2rs-m and 2m-cu). First tergite 4.4 times as long as posteriorly broad, smooth (Fig. 6). Second tergite twice as long as anteriorly broad (Fig. 6).

Head black; clypeus brownish yellow in lower half, mandible brownish yellow with teeth blackish; glossa and palps yellow, remaining mouthparts dark brown or fuscous. Antennal flagellum black, scape and pedicel dark brown. Mesosoma black. Tegula yellowish. Pterostigma brown. Legs predominantly brown; all coxae black; mid and hind tibiae and tarsi fuscous; hind femur apically pale. First tergite black. Metasoma behind first tergite predominantly brownish yellow; tergite 2 in basal 0.2, tergite 3 in basal 0.6, and following tergites more or less entirely dark brown to black dorsally.

Male. Labium almost reaching past posterior end of first metasomal tergite. Maxillary and labial palps not discernible, probably short. Antennal flagellum with 22 flagellomeres. Occipital carina dorsally fine but distinct, laterally and ventrally indiscernible. Mesopleuron very finely punctate peripherally, centrally (above foveate groove) polished and impunctate (Fig. 5). Fore wing (Fig. 3) with intercubitus (2rs-m) somewhat shorter than abscissa of cubitus between intercubitus and second recurrent vein (abscissa of M between 2rs-m and 2m-cu). Basal metasomal tergites slenderer than in female. Thyridial depression shallow. Fore and mid coxae slightly darkened with brown, tibiae and tarsi less infuscate than in female. Otherwise similar to female.

Holotype female (UAT), Mexico, Tamaulipas, NE of Miquihuana, Rancho Obed Hernández, 2500 m, Malaise trap, 25.IX–7.X.2011, coll. E. Ruíz-Cancino & J.M. Coronado-Blanco.

Paratype. 1 male (EMUS) Mexico, Nuevo León, 32 km W of Linares, San Pedro Iturbide, 26.X.1962, coll. H. & M. Townes, “Probles sp. 37 Tow. 1969”.

From the Latin brevis (small, short) and palpus (palp, feeler), after its short maxillary and labial palps.

Figures 1–6. 

Labilochus brevipalpis sp. n., holotype female (1, 2, 6) and paratype male (3–5). 1 antenna 2 head and mesosoma, lateral view 3 fore wing 4 head and mesosoma, dorsal view 5 mesopleuron 6 propodeum and base of metasoma, dorsal view.