Contributions to the knowledge of the Chinese Primeuchroeus Linsenmaier, 1968 (Hymenoptera, Chrysididae), with a key to species

Abstract The genus Primeuchroeus Linsenmaier, 1968 from China is revised and an illustrated identification key is produced for the first time. Three species are recorded from China, with one species, Primeuchroeus yongdaerianus Kim, new to China.


Introduction
Primeuchroeus Linsenmaier belongs to the tribe Chrysidini of the subfamily Chrysidinae (Kimsey & Bohart, 1991). Bohart (1988) revised the genus and divided it into five species-groups, with a key to all known species at that time. More detailed diagnosis and discussion of each species-group was published later by Kimsey and Bohart (1991). Linsenmaier (1997) considered three species, alces Linsenmaier, 1968, paradoxa Linsenmaier, 1968and tenuimediata Linsenmaier, 1968 belonged to the genus Chrysis. However, we follow the systematics proposed by Kimsey and Bohart (1991).
Presently 33 species of Primeuchroeus are known worldwide (Kimsey and Bohart 1991;Kim 2013), of which 26 are from the Australian region, four are from the Oriental region, one is from the Palaearctic region, one is from both the Oriental and the Palaearctic regions, and one is from the Afrotropical region (Kimsey and Bohart 1991;Madl and Rosa 2012;Kim 2013).
In China, before this study, only two species have been recorded from Taiwan by Tsuneki: Primeuchroeus crassiceps (Tsuneki, 1970) and Primeuchroeus kansitakuanus (Tsuneki, 1970). In this study, three species are recognized, with one new to China.

Materials and methods
All specimens were examined and described under stereomicroscope (Olympus SZ61). All photos were taken with a digital camera (CoolSNAP) attached to a Zeiss Stemi 2000-CS stereomicroscope. Images were processed using Image-Pro Plus software.
Abbreviations used in the descriptions as follows: F-I, F-II, F-III, etc. = flagellum I, flagellum II, flagellum III and so on; MOD = midocellar diameter; MS = malar space, the shortest distance between the base of mandible and the margin of compound eye; S-II spots = two oval dark spots on metasomal sternum II; TFC = transverse frontal carina; T-I, T-II, T-III, etc. = metasomal tergum I, tergum II, tergum III and so on.
Key to the Chinese species of Primeuchroeus Linsenmaier 1 Forewing with Rs long, about two times as long as stigma, and bent sharply in the middle (Fig. 23); lateral margin of T-III convex, with a small tooth basally (Fig. 27) (Tsuneki, 1970) Head. Scapal basin deep and impunctate, with transverse striae and a round pit anteromedially (Fig. 3). F-I slightly longer than F-II (Fig. 3). TFC absent (Fig. 3).
Colouration. Head and mesosoma metallic green, blackish along notauli. Mandible brown, with metallic green basally. Antenna black, with scape, pedicel and basal F-I metallic bluish-green. Tegula metallic bluish-green. Leg metallic bluish-green, with inner surface of tibia and tarsus brown. Metasoma metallic blue, with T-I metallic greenish-blue.
Male. Body length 4.3 mm (Figs 10, 11). Forewing length 3.1 mm. MS = 0.7 MOD. F-I 2.0× as long as wide. Subantennal space = 0.8 MOD. Differing from female as follows: vertex, mesosoma, T-I and T-II darker than those of female; forewing with discoidal cell more distinct than that of female (Fig. 14); apex of T-III rounder than that of female, without angle medially (Fig. 16).
Diagnosis. F-I slightly longer than F-II. TFC absent. Pronotum with an obtuse angle on each lateral margin. Forewing with Rs short, 0.6 times as long as stigma, ending obtusely. Lateral margin of T-III nearly straight, without tooth. (Tsuneki, 1970), female from Yunnan. 1 Habitus, dorsal view 2 habitus, lateral view.
Male. Unknown. Diagnosis. F-I distinctly longer than F-II. TFC distinct and double. Forewing with Rs long, 2.0-2.4 times as long as stigma, and bent sharply in the middle. Lateral margin of T-III convex, with a small tooth basally.
Colouration. Face metallic green, with yellow reflections. Mandible brown, with metallic green basally. Antenna black, with scape metallic green. Vertex, pronotum, mesonotum, and metanotum metallic bluish-green. with black colour. Tegula blackishbrown, with metallic blue hints. Leg with coxa and femur metallic green; tibia mostly brown, with slight metallic reflections; tarsus brown. Metasoma mostly black, with metallic green reflections posteriorly and laterally on each segment.
Male. No available specimens for this study. Diagnosis. TFC distinct and double. Forewing with Rs short, 0.6 times as long as stigma, and ending obtusely. Lateral margin of T-III nearly straight, without tooth.
Distribution. China (Yunnan); Korea. Biology. Unknown. Collected in July and August.
Remarks. According to Kim (2013), P. yongdaerianus belongs to the siamensis species-group. It is the first record to the Oriental region and to China. The specimens from Yunnan vary from those from Korea by tibia and tarsus brown, and with metallic blue on S-III.