Taxonomy of Sierola Cameron (Hymenoptera, Bethylidae) from China with three new species

The genus Sierola Cameron, 1881 (Hymenoptera, Bethylidae) from China is revised for the first time and three new species, i.e., S. brevicaputa sp. nov., S. limatulifascia sp. nov., and S. leleji sp. nov. are described. A key to the Oriental species is provided.


Introduction
The genus Sierola Cameron, 1881 belongs to the subfamily Bethylinae (Hymenoptera: Bethylidae). It is the largest genus in Bethylinae with 250 species and subspecies known to the world (Fullaway 1920(Fullaway , 1934Gordh and Móczár 1990;Gordh 1998;Terayama 2004Terayama , 2006Ward 2013;Santhosh 2017;Azevedo et al. 2018;Magnacca 2019Magnacca , 2020. This genus is very similar to Goniozus Förster, 1856 in having suture of metapectal-propodeal disc and dentate process of mesopectus absent, but can be distinguished from the latter by having 2R1 2 c of forewing closed. According to Gordh (1998), this genus may originate in Asia, and then invaded the Hawaiian Islands within the past few million years and radiated rapidly. Till now 214 species of this genus have been recorded from Hawaiian Islands, however, only one species, Sierola sinensis Fullaway, 1920, is known from China. In this paper, another three new species found in China are described. According to the label attached to the specimens, all the new species are parasitoids of Haplochrois theae (Kusnezov, 1916) (Lepidoptera, Elachistidae), which is a pest on tea plantations.

Materials and methods
Specimens examined in this study are deposited in the Institute of Insect Sciences, Zhejiang University, Hangzhou (ZJUH).
A Nikon stereomicroscope (SMZ800N) was used for observation. We used digital microscope Keyence (VHX-7000) to gain the photographs. Then edited them with the help of Adobe Photoshop CC 2018. The morphological terms follow Lanes et al. (2020) and the setation of forewing follows Magnacca (2020).
The methods as well as abbreviations for biometric measurements are as follows: AOL width between anterior and posterior ocellus, measured as minimum length in frontal view. DAO diameter of anterior ocellus, measured in frontal view. DEV distance between supra-ocular line and vertex crest in frontal view. DH maximum depth of the head in lateral view. DT depth (height) of the thorax, measured in lateral view from between the meso-and metacoxa ventrally to the dorsal surface of the mesonotum. LE maximum length of eye in lateral view. LH length of head, measured in lateral view, from apex of clypeus to vertex. LT length of the mesosoma excluding the pronotal collar. OOL shortest distance from a posterior ocellus to nearest eye margin. POL posterior ocellus line, measured as minimum width between posterior ocelli in frontal view. WF width of frons, measured in frontal view, its minimum width. WH width of head, measured in frontal view, its maximum width including eyes. WOT width of ocellar triangle, measured in frontal view, maximum width including ocelli.

Male. Unknown.
Etymology. This species is named in honor of the well-known Russian entomologist, an expert of Aculeata, Professor Arkady S. Lelej for celebrating his 75-anniversary.

Distribution. China (Zhejiang).
Comments. This species is similar to the species Sierola shimotsukeana Terayama, 2006 for the shape of head. But it can be distinguished by having 1M 2 c nearly rectangular, metapostnotal-propodeal disc coriaceous, and mandible light castaneous while S. shimotsukeana having 1M 2 c oval, posterior area of metapostnotal-propodeal disc smooth medially, and mandible black.

Distribution. China (Zhejiang).
Comments. This species can be distinguished from other species by having R1 2 v intersect apical portion of Rs 2 v at acute angle, and metapostnotum with median shiny longitudinal stripe elevated.

Discussion
The only record of this genus in China, Sierola sinensis, was published by Fullaway in 1920, and this paper is the first report about this genus from China after a hundred years since then. This genus was previously recorded in Macao (22°11.39'N, 113°32.54'E), and the new species reported in this paper were collected in Zhejiang Province (28°54.42'N, 118°31.05'E), which distinctly expanded the potential distribution of this genus in China.