﻿A new species of Passaloecus Shuckard (Hymenoptera, Crabronidae) from China, with a key to Oriental species

﻿Abstract A new species of Passaloecus Shuckard, P.birugatus Bashir & Chen, sp. nov., is described and illustrated from Yunnan Province, China. The new species can be easily distinguished from known species of Passaloecus by its very long petiole, which is distinctly longer than wide, obscure scrobal suture, propodeum rugae and striations, body punctation, and coloration. An identification key to the Oriental species of Passaloecus is given.


Introduction
The members of the genus Passaloecus Shuckard, 1837 (Hymenoptera, Crabronidae) are small predatory wasps.The genus belongs to the tribe Pemphredonini, subtribe Pemphredonina (Pulawski 2023).The subtribe Pemphredonina are recognized by their forewing, which has three discoidal cells and two recurrent veins (Kim and Yang 2010).Among genera of the subtribe Pemphredonina, Passaloecus is differs from the closely related genus Polemistus de Saussure in lacking long setae on the ventral gena, having the inner orbits almost parallel, and a rarely found omaulus; from other genera, Diodontus Curtis and Pemphredon Latreille, in this subtribe, Passaloecus differs in having the labrum roundly produced, a horizontal hypersternaulus, hind-tibia lacking a series of spines, a complete episternal sulcus, and females without a pygidial plate (Bohart and Menke 1976;Bashir et al. 2021).Females of Passaloecus build internal cell partitions from plant resins and construct their nests in soil, stems, soft wood, or abandoned insect nests (Antropov and Perkovsky 2009;Kim and Yang 2010).
The present paper records a new species of the genus Passaloecus, described and illustrated from the Oriental Region of China, and provides an illustrated identification key to the Oriental Passaloecus.

Materials and methods
Specimens examined were collected from Yunnan Province, China, using Malaise traps.Specimens were observed with the help of a Nikon microscope (SMZ745).For the terminology, we follow Bohart and Menke (1976), Harris (1979), andBashir et al. (2020).Photographic images were taken using a Leica (S8APO) stereoscopic microscope attached to a computer, processed using Adobe Photoshop 8.0, and prepared into plates using Adobe Illustrator (2019).Measurements and ratios were acquired as the maximal length with an ocular scale on a Nikon microscope (SMZ745).The description of the new species is based on the holotype, and the differences in the paratypes are given between square brackets.
The abbreviations are used in the species descriptions as follows:  Free margin of clypeus truncate (Fig. 13 triangle and vertex behind ocelli with midsize punctures, close to each other); anterior carina of pronotal collar lacking (strong anterior carina present); notauli distinctly impressed (notauli slightly impressed); mesopleuron posteriorly without longitudinal rugae (mesopleuron posteriorly with short, sparse, longitudinal rugae); petiole distinctly longer than wide (petiole distinctly shorter than wide).The male can be distinguished from the closely related Oriental species Colour pattern: body black except the following: labrum, tegula and mandible apically reddish brown, remaining mandible ivory to yellowish [yellow]; palpi ivory [yellow]; scape ivory beneath, black above; pronotal lobe creamy white; forewing veins dark brown and hindwing veins light brown; tibiae and tarsi reddish brown to fulvous, remaining legs black; clypeal setae silvery (Fig. 31).
Etymology.The name birugatus is derived from the Latin prefix bi-(= two) and the Latin word rugatus (= rugose), with reference to the propodeal dorsal with two strong longitudinal rugae.