Diagnosis: Diagnosis: This species can be distinguished from the similar P. clypealis Faester (1947) by the following combination of characters: petiole distinctly longer than wide; flagellomeres IV–VIII beneath with tyloids; sternum I without keel; pronotal collar without anterior carina or antero-lateral angle; anterior slope of scutum nearly vertical and high. P. clypealis Faester has the following characters: petiole short; flagellomeres III-VII beneath with tyloids; sternum I with a longitudinal keel; pronotal collar with conspicuous anterior carina, anterolateral angle moderately produced; anterior slope of scutum with usual shape.

These two species can be distinguished from the other species of the genus by the following combination of characters: pronotal lobe ivory to yellowish; lower frons coarsely leathery; hypersternaulus and episternal sulcus distinctly crenate; scrobal sulcus lacking, just insignificantly impressed; spinose tubercles on hind margin of gastral tergum VI absent.

Description: Male. Body length 6 mm. Black; apical mandible reddish brown, remainder ivory to yellowish; labrum, pedicel, flagellomere, tegula and forewing vein dark brown; palpi and pronotal lobe ivory to yellowish; scape beneath with small yellowish spot basally; fore tibiae and tarsi reddish brown to dark brown; mid and hind tibiae and tarsi dark brown. Setae on clypeus dense, somewhat elongate, silvery (Fig. 20).

Mandible bidentate apically. Labrum not constricted subapically. Clypeus slightly convex medially, with midsize, dense punctures that are 0–1 × diameters apart; free margin slightly produced medially, nearly truncate apically (Fig. 20). Lower frons coarsely leathery; interantennal tubercle inconspicuous; frontal median carina lacking (Fig. 20). Median and upper frons markedly leathery, with fine, dense punctures that are 0–1 × diameters apart. Ocellar triangle area slightly convex, coarsely leathery, with fine, dense punctures. Vertex with fine, dense punctures that are 0–1.5 × diameters apart, and dense, slender, transverse striation, distinctly leathery. Gena with fine, dense punctures that are 1–2 × diameters apart, coarsely leathery. Occipital carina usual, single carina. HW: HLD: HLF = 71: 36: 57; HW: EWd: EW: TW: EL = 71: 15: 25: 18: 46; POD: OOD: OCD = 9: 11: 13; length of scape: length of pedicel: length of flagellomere I: width of flagellomere I: length of flagellomere II: width of flagellomere II = 20: 8: 9: 6: 10: 6. Flagellomeres IV–VIII beneath with narrow, long tyloids (Fig. 21).

Pronotal collar without anterior carina or antero-lateral angle. Scutum coarsely leathery, with midsize, dense punctures that are 0–1 × diameters apart, anterior slope nearly vertical and somewhat high; scutal patches absent; admedian line weakly impressed, extending to one third of scutum; prescutal sutures slightly impressed, extending to one third of scutum; parapsidal line distinct, long. Scutellum slightly leathery, with midsize, dense punctures that are 0–1 × diameters apart. Metanotum slightly leathery, with fine, sparse punctures that are 0–1 × diameters apart. Mesopleuron coarsely leathery, with fine, dense punctures that are 0–1 × diameters apart; hypersternaulus and episternal sulcus distinctly crenate; scrobal sulcus lacking, just insignificantly impressed; omaulus absent. Metapleuron shiny. Propodeal enclosure not delimited by carina, with slender, dense longitudinal rugae, mixed with several short, transverse rugae medially (Fig. 22); posterior surface irregularly rugose (Fig. 22); lateral surface shiny, nearly smooth anteriorly, somewhat with evanescent, dense, oblique longitudinal striation, median and posterior areas with slender, long, irregular, oblique longitudinal rugae.

Petiole distinctly longer than wide (Fig. 23); PL: PW: LTI: WTI = 15: 8: 48: 31. Gastral segments half mat, slightly leathery, with fine, dense punctures that are 0–2 × diameters apart; keel of sternum I lacking; sternum II deeply impressed basally; gaster distinctly constricted between terga I and II; spinose tubercles on hind margin of gastral tergum VI absent. Male genitalia (Figs. 24–26).

Female: unknown.

Specimen examined: Holotype: ♂, China: Tibet: Chaya: Jitang, altitude 3600 m, 30°44'N 97°20'E, 8.VIII.1976, coll. Yinheng Han. The specimen is deposited in the Institute of Zoology Chinese Academy of Sciences, Beijing, P. R. China.

Distribution: China: Tibet.

Etymology: The name petiolatus is the Latin word (= with petiole), referring to the petiole distinctly longer than wide, which is one of the main recognition characters of this species.