First record of Labium (Hymenoptera: Ichneumonidae: Labiini) in South America with description of a new species from Brasil

Labium is a primitive transantarctic genus which parasitizes ground-nesting halictid bees and until now has been known only from the Australian Region. Diagnostic features include its large exposed labrum (as long as clypeus) ; elongate mandible with upper tooth much shorter and smaller than lower tooth; slender 1st gastric tergite with spiracle distad of middle; and short, concealed ovipositor which is slender, depressed, and without notch or nodus. Labium wahli is now described from south Brazilian rain forest. It differs from the Australian species by its longer flagellum which is only slightly thickened apicad and because it has no crests at base of the notauli Resumen. Labium es un género primitivo de distribución transantártica, conocido hasta ahora sólo de la Región Australiana, y que parasita abejas de la familia Halictidae que nidifican en la tierra. Puede reconocerse por su labro grande y descubierto (tan largo como el clípeo); mandíbula alargada con el diente superior mucho más corto y pequeño que el diente inferior; primer terguito algo esbelto con el espiráculo ubicado detrás de la mitad; y el ovipositor corto que no se extiende más alla del ápice del gáster y que es fino, deprimido, y no tiene ni hendidura ni nodo. Se describe como nueva la especie Labium wahli que habita en la selva lluviosa del sur de Brasil , diferenciándose de las especies australianas por su flagelo más largo, fino y sólo levemente ensanchado hacia el ápice y porque no tiene una cresta en la base de cada notaulo. 204 Volume 17, No. 3-4, September-December, 2003, INSECTA MUNDI Townes (1969) was the first to report Labium from South America but did not describe the new species which he had collected in 1966 at Teresópolis in the south Brazilian coastal mountains. In 1969 Porter collected additional Brazilian material at Serra da Bocâina in São Paulo State. Through the kindness of Dr. David B. Wahl , director of the American Entomological Institute, I have been able to study the specimens collected by Townes and now describe this South American species, which is closely related to its Australian congeners in Labium (s. str. ). Labium wahli Porter, new species (Figs. 1-3) Description: Female. Color: antenna brownish black; head, mesosoma, and gaster shining dark brown with pale yellow or brownish yellow markings as follows: on palpi ; most of mandible except for teeth; labrum; clypeus; malar space; on much of face except for brownish toward its center, around anterior tentorial pits, and below antennal sockets; broadly on facial orbits up to level of front ocellus; sordidly on pronotal dorsum including collar, weakly on lower pronotum anteriad and on upper hind corner of pronotum around spiracle; weakly on tegula; extensively on mesepimeron ; vaguely on hind margin of metanotum and on prescutellar carina; obscurely on apical margin of first gastric tergite, more broadly on hind margins of tergites 2 and 3, and more narrowly and weakly on apices of succeeding tergites; wings very lightly brownish infumate with subdued metallic reflections, the veins translucently pale brown with stigma, most of prestigma, and part of costal vein light yellowish; fore and mid legs yellow to brownish yellow with darker brown on much of coxae, extensively on femora, dorsally and dorso-laterally on tibiae, and toward apex on fifth tarsomere; hind leg brown on most of coxa, on trochanter and trochantellus except for yellowish ventrad, on femur except for yellowish narrowly on apex above, paler brown on tibia with yellowish at apex, and on tarsus yellowish with brownish staining toward apex of first segment and on apical 0.25 of fifth segment. Length of fore wing: 9.4 mm. Flagellum: very long, 0.9 as long as fore wing, only faintly enlarged toward apex, with 35 segments; 1st flagellomere 3.6 as long as deep at apex and 1.5 as long as 2nd flagellomere. Mandible: elongate, gradually tapered toward apex, with upper tooth strong and elongate but lower tooth very short, less than 0.5 as long as upper. Labrum: strongly exposed and very large, 1.0 as long as wide, longer than clypeus . Labium: long, anthophilous , glossa elongate, deeply incised and bilobed at apex with each lobe tapering to a narrow apical point. Clypeus: transversely convex, 3.0 as broad as long, its apical margin broadly concave (seen in ventral view). Malar space: 0.41 as long as basal width of mandible. Occipital carina: sharp throughout, complete across dorsum of head and laterally percurrent to base of mandible. Hypostomal carina: absent. Epomia: strong, sharp, slightly curved, not forming a crest above at basal end of notaulus. Mesoscutum: smooth and glossy with numerous tiny punctures which emit short, rather dense setae; notauli faintly traceable on basal 0.3 of mesoscutum so that a median lobe a little higher than the adjacent lateral lobes is formed anteriorly; no trace of parapsidal furrows. Mesopleuron: polished with many tiny punctures; prepectal carina strong on lower 0.4 of mesopleuron where it ends abruptly dorsad without approaching anterior margin of mesopleuron ; subalarum large and swollen; sternaulus and postpectal carina absent. MetaFigure 1. Labium wahli, female paratype. Front view of head showing large exposed labrum, clypeus, and mouthparts. 205 INSECTA MUNDI, Vol. 17, No. 3-4, September-December, 2003 pleuron: convex with many but well spaced small punctures which emit long, overlapping setae, with surface smooth and polished, and with submetapleural carina expanded on its basal 0.5 into a large lobe which overlaps base of mid coxa. Propodeum: spiracle large, narrow, 4.0 as long as wide; areolation with full complement of longitudinal and transverse carinae; area basalis large, rectangular, 1.4 as wide as long; areola 1.8 as long as wide, separated from petiolar area by a strong carina. Gaster: elongate fusiform, 0.6 as long as mesosoma. First gastric tergite: elongate, gently widened toward apex, with spiracle located well distad of middle but far from hind margin of tergite; postpetiole 1.0 as wide at apex as long from spiracle to apex; longitudinal carinae absent or obsolete, ventral longitudinal carina weakly suggested on petiole; first sternite 0.5 as long as first tergite; surface of postpetiole smooth and highly polished with a few scattered tiny punctures; 2nd tergite polished with a large but weak basal thyridium and scattered tiny setiferous punctures; 3rd tergite like 2nd but more densely setose and punctate; 4th and following tergites with denser fine punctures and extensively overlapping setae. Epipleura of tergites 1-4 very broad and almost touching medio-ventrally, those of tergites 1 and 2 separated from their tergite by a sharp, percurrent carina , that of 3rd tergite separated on basal 0.3 by a sharp carina which becomes weaker apicad, that of 4th tergite separated by a weak crease which is carinate only near base, epipleura of following tergites fused with their tergite. Ovipositor: sheath short and Figure 2. Labium wahli, female paratype. Lateral view of entire insect. 206 Volume 17, No. 3-4, September-December, 2003, INSECTA MUNDI broad, a little rounded apically, not exceeding apex of gaster; ovipositor shaft not exserted, fully concealed at rest, when displaced it is seen to be long and slender, gently up-curved, depressed, with ventral valves overlapping dorsal valves on tip, with strong crowded ridges, and without a nodus or dorsal notch. Wing venation: areolet large, 1.8 as wide as high with intercubiti strongly convergent above, 2nd abscissa of radius 0.7 as long as 2nd intercubitus ; 2nd recurrent distad of middle of areolet so that 2nd abscissa of cubitus is only 0.4 as long as 1st, 2nd recurrent with 1 bulla and strongly thrust mesad, outlining an acute angle whose vertex is near middle of vein; radial cell 2.5 as long as high; 1st abscissa of radius weakly bisinuate, more strongly sclerotized than adjacent veins, 3rd abscissa of radius also bisinuate but less sclerotized than 2nd abscissa; hind wing costella short, apically truncate, with 6 hamuli; nervellus broken above middle (upper abscissa 0.7 as long as lower); discoidella complete to hind margin of wing; axillus vestigial, on hind margin of wing. Legs: fore tibia slender basally and a little swollen beyond base but hardly clavate, without a small tooth on outer side at apex, dorso-externally with many long spine-like setae ; mid tibia slender, on outer surface with numerous strong spine-like setae, its apex with robust somewhat recurved spines dorsally and externally; hind coxa stout, swollen toward middle, 2.5 as long as deep; hind femur long but stout, 3.8 as long as high, smooth and polished with many tiny punctures that emit long, more or less overlapping setae; hind tibia with strong spine-like setae which are sparser than those on mid tibia, its apical spines very strong; hind Figure 3. Labium wahli, female holotype. Lateral view of apex of gaster, showing structure of the (displaced) ovipositor. tarsus with 1st segment only slightly compressed, widening toward apex, 1.6 as high at apex as at middle and 1.8 as long as 2nd tarsomere, on its apex with a circlet of about 14 strongly sclerotized, splayed, apically acuminate spines; tarsal claws of all legs without teeth but with a large, slender empodium(0.6