Pison pistillum Menke

Pulawski, Wojciech J., 2018, A Revision of the Wasp Genus Pison Jurine, 1808 of Australia and New Zealand, New Guinea, and the Pacific Islands (Hymenoptera: Crabronidae), Proceedings of the California Academy of Sciences 65, pp. 1-584 : 526-529

Pison pistillum Menke

Figures 1276-1287.

Pison pistillum Menke, 1988:91 , ♀. Holotype: ♀, Papua New Guinea: Western Highland Province : Bayier River (AEI), not examined.

RECOGNITION.– Pison pistillum shares with P. woji (whose male is unknown) the combination of the second recurrent vein ending on submarginal cell II near its midlength (Fig. 1287) and a conspicuously elongate gastral segment I (Fig. 1283): length of tergum I 2.0 × apical width, distance between gastropropodeal articulation and spiracle 1.7 × distance between spiracles. As in P. woji , the ommatidia are markedly larger in the lower half of the eye than those in the dorsal half (Fig. 1278). The female is unique in having the eye emargination roundly acute rather than round- ed (Fig. 1280). The species differs from P. woji by a number of characters in addition to the eye emargination: clypeus (Fig. 1276) with a well defined median lobe (lobe absent in P. woji ), the middle supraantennal carina present (absent in P. woji ), the dorsal length of flagellomere I 4.0-4.5 × the apical width in the female and 3.5 × in the male (rather than 1.8-1.9 × in woji ), the forewing media (Fig. 1282) diverging from M+Cu before crossvein cu-a (in P. woji diverging at cu-a or shortly beyond it), sternum II impunctate apicomesally (punctate throughout in P. woji ), the gaster black (gastral segment I ferruginous in P. woji ), the dorsomedian part of the female clypeus elevated, separated by an angle from the ventral portion (no elevation in P. woji ), female tergum VI carinate apically (not carinate in P. woji ), and length of 10.0- 10.5 mm in the female and 7.3 mm in the male (rather than 5.4-6.5 mm).

Menke (1988) thought that the shape of the submarginal cell III separates these two species. Indeed, his picture of the holotype forewing shows a submarginal cell III with the foremargin markedly shorter than the hindmargin. In the specimen from the New Britain, however, the foremargin of the submarginal cell III is only slightly shorter than the hindmargin (Fig. 1282), exactly as in P. woji .

DESCRIPTION.– Frons dull, conspicuously aciculate, and with evanescent, minute punctures averaging about one diameter apart. Distance between antennal socket and orbit smaller than sock- et diameter in female, equal to socket diameter in male. Occipital carina in female slightly expand- ed at ventral end. Gena narrow in dorsal view (Fig. 1279). Ommatidia becoming larger toward inner eye margin, larger in ventral eye half than those in dorsal half (Fig. 1278); eye notch roundly acute in female (Fig. 1280), less distinctly so in male. Labrum semicircularly emarginate carinate. Gastral segment I narrow in basal half, broadened in apical half, conspicuously elongate (Fig. 1283): length of tergum I 2.0 × apical width in female, 1.9 × in male, distance between gastropropodeal articulation and spiracle 1.7 × distance between spiracles in female, 1.4 × in male; punctures minute, about one diameter apart. Sternum II minutely punctate, impunctate apicomesally.

Setae silvery, appressed on frons, postocellar area, lower gena, scutum, and tergum I; nearly completely concealing integument on clypeus. Apical depressions of terga without setal fasciae; with silvery appressed vestiture at anterolateral corner of tergum II and near lateral margin of terga III and IV.

Head, thorax, propodeum, and gaster black except following yellow brown: scapal venter, pedicel venter, ventral two-thirds of clypeus in female, basal half of mandible, palpi, and tegula, also hindmargin of pronotal lobe in holotype. Legs in holotype yellow brown except black hindtarsomeres III-V; in female from New Britain coxae partly, trochanters and very base of femora yellow brown, most of femora black, foretibia mostly yellow brown, mid- and hindtibiae black except yellow brown basally and apically, and tarsi yellowish; in male from Solomon Islands forecoxa and all femora black, tibiae largely black, partly brown, and tarsi yellow; spurs whitish.

♀.– Upper interocular distance equal to 0.96-1.00 × lower interocular distance; ocellocular distance equal to 0.3 × hindocellar diameter, distance between hindocelli equal to 0.3 × hindocellar diameter; eye height equal to 1.26 × distance between eye notches. Free margin of clypeal lamella obtusely tridentate in holotype, almost straight in specimen from New Britain (Fig. 1276); dorsomedian part of clypeus elevated, separated by angle from ventral portion. Dorsal length of flagellomere I 4.0-4.5 × apical width, of flagellomere IX 1.7 × apical width. Mandible: trimmal carina with small obtuse tooth near base, without incision. Tergum VI with median carina apically. Length 10.0- 10.5 mm; head width 1.8 mm .

♂.– Upper interocular distance equal to 0.80 × lower interocular distance; ocellocular distance equal to 0.5 × hindocellar diameter, distance between hindocelli equal to 0.5 × hindocellar diameter; eye height equal to 1.28 × distance between eye notches. Free margin of clypeal lamella arcuate, with ill-defined, short median point (Fig.

1277). Dorsal length of flagellomere I 3.5 ×

apical width, of flagellomere X 1.4 × apical width. Sternum VIII with apical margin projecting mesally, concave on each side of projection (Fig. 1284). Genitalia: Figs. 1285,

1286. Length 7.3 mm; head width 1.9 mm.

GEOGRAPHIC DISTRIBUTION (Fig. 1287).–

Papua New Guinea including New Britain, and

Solomon Islands.

RECORDS.– PAPUA NEW GUINEA: New

Britain: Vunabakan 10 km E Keravat (1 ♀, BISH,

determination by A. Menke). Western Highland

Province: Bayier River (Menke, 1988).

FIGURE 1287. Collecting localities of Pison pistillum

SOLOMON ISLANDS: Santa Isabel Island:

Menke

Kolotuve (1 ♂, BISH) .