Arpactophilus arha sp. nov.

(Figs. 27–28)

Diagnosis. Arpactophilus arha is the only New Caledonian species in the genus with the combination of a bulge on metasomal sternum II (Fig. 28, and as in Fig. 2), yellow markings on the lower frons, a yellow clypeus with an apical margin medially projecting and with a broad V-shaped incision (Fig. 27).

Description. FEMALE: Total length 6.0– 7.3 mm, mean = 6.7 mm; forewing length 4.0– 4.3 mm, mean = 4.1 mm.

Body black, with areas of yellow markings. Yellow: apical half of clypeus; mandible; labrum; palpi; area around mandibular base; scape; pedicel; flagellum basally; band on frons close to inner compound eye margin, extending from clypeus to middle of frons (Fig. 27); anterior pronotal margin; pronotal lobe; tegula; legs. Flagellum apically brown. Wings hyaline; pterostigma dark brown.

Head about as long as wide in frontal view. Apical margin of clypeus medially projecting, with broad V-shaped incision (Fig. 27). Apical margin of labrum medially projecting, with broad U-shaped incision. Ventral mandibular tooth about ¼–1/5 of total mandibular length, not reaching opposite mandibular base. Palpal formula 5:4. Frons imbricate, with fine and dense punctation and associated setae. Frontal carina present from median ocellus to midlength of clypeus. Scape 4.1 × as long as wide. Ocellar triangle anterior of tangent between upper posterior orbits of compound eyes, lateral ocelli anterior of tangent by approximately their diameter. Occipital carina continuous, but inconspicuous dorsally. Gena imbricate, with setae sparser than on frons, without tubercles, spines, or dorsoventral carina. Hypostomal midventral line carinate, with bordering short transverse carinulae on hypostomal integument, not angulate.

Mesosoma about 2.0 × as long as wide in dorsal view. Propodeum about 1.1 × as long as wide in dorsal view. Mesosoma imbricate with additional dense punctation (Fig. 28), except propodeum; lateral surface of propodeum transversely carinulate; dorsal surface of propodeum coarsely reticulate (similar to pattern in Fig. 19). Non-pitted sulcus present posterior of fine mesoscuto-mesoscutellar sulcus. Hypersternal sulcus absent. Metafemur 3.2 × as long as wide. Metatibia without differently colored area apically. Pretarsal claws without teeth. Forewing with two submarginal cells; anterior border of submarginal cell II shorter than posterior border. Hind wing with five distal hamuli.

Metasoma matt, punctation sparse (Fig. 28). Metasomal sternum II swollen medially, forming bulge (as in Fig. 2). Pygidium with narrow brush of silk setae apically.

MALE: Differences from female aside from genitalic structures: apical margin of clypeus not as well defined. Metasomal sternum VIII narrow and pointed.

Remarks. Arpactophilus arha can easily be identified. It has head markings similar to those of A. pije, but is distinguishable by its the prominent bulge on sternum II (Fig. 28 and as in Fig. 2). Among those species with a bulge on the metasomal sternum II it is the only one with prominent yellow markings on the lower frons. Arpactophilus webbi is the only species of this latter group that also has a yellow clypeus, but the two species differ noticeably in the shape of the apical margin of the clypeus, which is medially projecting, with broad V-shaped incision in A. arha (Fig. 27).

Material examined. HOLOTYPE ♀: “ NEW CALEDONIA 12038: 2215’S x 16649’E, 280m, Pic du Pin, site 1. 23 Dec 2004– 12 Jan 2005. Burwell, Wright. malaise, rainforest [QM].

PARATYPES 6♀, 1♂:

♀: (1x) “ NEW CALEDONIA 8920: 2217’S x 16654’E, 250m, Pic du Grand Kaori. 21 Nov 2001 – 29 Jan 2002. G. Monteith. Malaise trap [QM]; (1x) “ NEW CALEDONIA 9960: 2206’S x 16639’E, 160m, Riv. Bleue, Panoramic track 20 Sep–11 Nov 2000. Burwell & Skevington. Malaise [QM]; (1x) NEW CALEDONIA 11846: 2217’S x 16653’E, 250m, Pic du Grand Kaori, site 1. 22 Nov –22 Dec 2004. Wright, Burwell. Malaise, rainforest [QM]; (1x) “ NEW CALEDONIA 11864: 2214’S x 16650’E, 280m, Pic du Pin, site 2. 25 Nov –23 Dec 2004. Burwell, Wright. Malaise, rainforest [QM]; (1x) NEW CALEDONIA 11882: 2219’S x 16655’E, 480m, Foret Nord, site 1. 1–22 Dec 2004. Burwell, Wright. malaise rainforest [QM]; (2x) NEW CALEDONIA 12074: 2219’S x 16655’E, 480m, Foret Nord, site 1. 22 Dec 2004– 9 Jan 2005. Burwell, Wright. Malaise, rainforest [ZMB].

♂: (1x) NEW CALEDONIA 12074: 2219’S x 16655’E, 480m, Foret Nord, site 1. 22 Dec 2004– 9 Jan 2005. Burwell, Wright. Malaise, rainforest [QM]; (specimen lost in SEM: (1x) “ NEW CALEDONIA 11864: 2214’S x 16650’E, 280m, Pic du Pin, site 2. 25 Nov –23 Dec 2004. Burwell, Wright. Malaise, rainforest [QM]).

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