Pison trukense Yasumatsu

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 : 565-566

Pison trukense Yasumatsu

Figures 1372-1376.

Pison trukense Yasumatsu, 1953:147 , ♀, ♂. Holotype: ♂, Caroline Islands: Chuuk Islands (formerly Truk): Tol: Olei (ELKU), examined. – Yasumatsu, 1953:136 (in list of Pison of Pacific islands ); R. Bohart and Menke, 1976:336 (in checklist of world Sphecidae ).

RECOGNITION.– Pison trukense can be recognized by the following combination: the setae of the head and thorax are silvery, appressed on tergum I, on te scutum markedly shorter than the midocellar diameter, on the lower gena sinuous and slightly longer than the midocellar diameter; the second recurrent vein is interstitial with second intersubmarginal vein or nearly so; punctures of sternum II are minute, several diameters apart near the center; and the apex of the marginal cell is markedly closer to the wing apex than that of the third submarginal cell. Additionally, the punctures of the propodeal dorsum are more than one diameter apart except laterally (Fig. 1375), the posterior propodeal surface has well-defined transverse ridges, and only tergum I has a silvery apical fascia. Pison reichingeri is similar, but differs as follows: the punctures of the propodeal dorsum (Fig. 1356) are less than one diameter apart (in some specimens several diameters apart adjacent to the midline); the posterior propodeal surface is punctate dorsally, with several transverse ridges ventrally; and at least terga I-III have a silvery, apical fascia. Pison novocaledonicum is also similar, and differs mainly in having the dorsal half of the posterior propodeal surface punctate and not ridged.

DESCRIPTION.– Frons dull, microsculptured, with well-defined punctures that average up to two or more diameters apart in female, slightly more than one diameter apart in male (Fig. 1374). Gena narrow in dorsal view. Labrum not emarginate. Anteromedian pronotal pit transversely elongate, about as long as midocellar diameter. Scutum not foveate along flange, without longitudinal ridges adjacent to posterior margin; scutal punctures well defined, unevenly distributed (many punctures on disk several diameters apart, other punctures less than one diameter apart); interspaces unsculptured. Tegula not enlarged. Mesopleural punctures well defined, less than one diameter apart in some specimens, but in most specimens several punctures near center more than one diameter apart; interspaces unsculptured. Postspiracular carina present, slightly longer than midocellar diameter. Metapleural sulcus costulate between dorsal and ventral metapleural pits. Propodeum with carina between dorsum and side absent in some specimens, in others extending up to half height of posterior surface; most of dorsum unridged, punctate (punctures more than one diameter apart except laterally), with longitudinal ridges only at very base, and also with short transverse ridges along midline, middle sulcus evanescent (Fig. 1375); side unridged, with well-defined punctures that average about two diameters apart near center in female, in male about one diameter apart; posterior surface transversely ridged, punctate between ridges. Posteroventral forefemoral surface with minute punctures that average 2-3 diameters apart. Hindcoxal dorsum with outer margin sharply carinate near apex only. Punctures of tergum I fine, several diameters apart anterior of apical depression. Sterna punctate throughout, punctures of sternum II several diameters apart mesally.

Setae silvery, subappressed to suberect on upper frons, appressed on postocellar area, on scutum suberect but markedly shorter than midocellar diameter, appressed on tergum I; on lower gena sinuous, up to 1.5 × midocellar width; on clypeus not concealing integument in female, largely concealing in male. Apical depression of tergum I, and only laterally, with ill-defined silvery, setal fascia; other terga without such fasciae.

Body all black.

♀.– Upper interocular distance equal to 0.48-0.50 × lower interocular distance; ocellocular distance equal to 0.3 × hindocellar diameter, distance between hindocelli equal to 0.6 × hindocellar diameter; eye height equal to 1.04-1.06 × distance between eye notches. Free margin of clypeal lamella roundly arcuate (Fig. 1372). Dorsal length of flagellomere I 3.0-3.1 × apical width, of flagellomere IX 1.7 × apical width. Mandible: trimmal carina with minuscule incision at about midlength. Tergum VI apically with median carina about as long as midocellar width. Length 8.2-9.0 mm; head width 2.5-2.7 mm.

♂.– Upper interocular distance equal to 0.62 × lower interocular distance; ocellocular distance