Arpactophilus iaai sp. nov.

(Figs. 61–62)

Diagnosis. Arpactophilus iaai is the only New Caledonian species in the genus with the combination of a dorsallyinterrupted occipital carina (Fig. 6), yellow tibiae and light reddish-brown metasoma, and a bulge on metasomal sternum II (Fig. 62).

Description. FEMALE: Total length 4.9 mm; forewing length 2.7 mm.

Body black, with areas of yellow and brown. Yellow: mandible laterally at base; palpi; anterior pronotal margin; pronotal lobe apically; tegula; coxae apically; trochanters; femora apically; tibiae; tarsi. Brown: most of mandible; antenna; most of coxae; most of femora, metafemur darker. Metasoma light reddish-brown (Fig. 62). Wings hyaline; pterostigma light brown. Labrum not visible.

Head about 1.2 × as long as wide in frontal view. Apical margin of clypeus strongly projecting, with shallow concave incision medially and a small tooth along margin below tangent of scape. Labrum not visible. Ventral mandibular tooth about ¼–1/5 of total mandibular length, not reaching opposite mandibular base. Palpal formula probably 5:4 (not completely visible). Frons colliculate, with short setae. Frontal carina present from median ocellus to midlength of clypeus, forming small point at basal clypeal margin. Scape 3.3 × as long as wide. Ocellar triangle anterior of tangent between upper posterior orbits of compound eyes, lateral ocelli anterior of tangent by more than their diameter. Occipital carina interrupted dorsally (Fig. 6). Gena imbricate with sparse punctation and associated setae, without tubercles, spines, or dorsoventral carina. Hypostomal midventral line carinate with bordering sparse and short transverse carinulae on hypostomal integument, not angulate.

Mesosoma about 2.0 × as long as wide in dorsal view. Propodeum about 0.9 × as long as wide in dorsal view. Mesosoma imbricate (Fig. 62), weakly punctured dorsally, except on dorsal surface of propodeum; lateral surface of propodeum also transversely carinulate; dorsal surface of propodeum coarsely reticulate (similar to pattern in Fig. 18). Broadly pitted sulcus present posterior to mesoscuto-mesoscutellar sulcus. Hypersternal sulcus absent. Metafemur 2.6 × as long as wide. Apical area on metatibia only slightly darker than remainder of tibia, barely visible. Pretarsal claws without teeth. Forewing with two submarginal cells; anterior border of submarginal cell II about one-half as long as posterior border. Hind wing with five distal hamuli.

Metasoma polished, with sparse punctation (Fig. 62). Metasomal sternum II swollen medially, forming bulge (as in Fig. 2). Pygidium with narrow row of silk setae.

MALE: Difference from female aside from genitalic structures: clypeus not projecting medially, but with two small teeth; yellow on mandible more distinct. Metasomal sternum VIII narrow.

Remarks. Arpactophilus iaai is somewhat similar to A. futuna in body size and coloration, but can easily be distinguished by the presence of the genal spine (Fig. 13) and the flat sternum II of the latter species (as in Fig. 1). Among those species with the combination of a reddish metasoma and a bulge on the metasomal sternum II (as in Fig. 2) A. iaai is most similar to A. arboreus, but can be identified by its mostly brown mandible and scape, which is yellow in the latter species.

Material examined. HOLOTYPE ♀: “Nouvelle Calédonie, Pinda 30m, 18.IV.1995, Réc. Chazeau & Jourdan [MNHN].

PARATYPE 1♂: “Nouvelle Calédonie, Pinda 30m, 18.IV.1995, Réc. Chazeau & Jourdan [MNHN].

Etymology. The specific epithet is taken from the name Iaai, one of the New Caledonian native languages. It is treated as a noun in apposition.