﻿Revisionary notes on the genus Aulacocentrum Brues (Hymenoptera, Braconidae, Macrocentrinae) from Vietnam

﻿Abstract This paper contains descriptions and illustrations of five new species of the genus Aulacocentrum Brues, 1922, from Vietnam, viz. Aulacocentrumassitum Long & Pham, sp. nov.; A.glabrum Long, sp. nov.; A.imparum Long & van Achterberg, sp. nov.; A.intermedium Long & van Achterberg, sp. nov.; and A.simulatum Long, sp. nov. Additionally, Aulacocentrumseticella van Achterberg & He is newly recorded for Vietnam’s braconid fauna. A checklist and a key to the Oriental and East Palaearctic Aulacocentrum species is provided and the in-country distribution of the Vietnamese species is given.


Introduction
Macrocentrinae Foerster, 1863, is a relatively small subfamily of Braconidae Nees, 1811, comprising eight recognised genera.Aulacocentrum Brues, 1922 is a rather small genus distributed in the Old World tropics and southern part of the East Palaearctic region.Up to now, Aulacocentrum comprises nine valid species, of which four species are known from the Oriental region (but the position of one is uncertain) and one species additionally from the East Palaearctic region.
Aulacocentrum differs from other macrocentrine genera by having the first metasomal tergite with fine transverse striation and vein SC+R1 of hind wing strongly bent basally, both absent in A. glabrum sp.nov., but has typical narrowed marginal cell of hind wing (Fig. 4F).A detailed diagnosis of the genus Aulacocentrum was given by van Achterberg (1993b) and He and van Achterberg (1994).
Previous records indicate that Aulacocentrum species are mainly endoparasitoids of pyralid larvae (Lepidoptera) (He and van Achterberg 1994;Yu et al. 2016).In this paper seven species of the genus are reported from Vietnam, of which five are new to science and one species is newly recorded for the fauna of Vietnam.

Materials and methods
All Aulacocentrum specimens, including holotypes and paratypes, are deposited in the Institute of Ecology & Biological Resources (IEBR) at Ha Noi, Vietnam.The collecting was by light traps in open spaces in the forest, but A. seticella was collected in Malaise traps.
We used an Olympus® SZ61 binocular microscope for this study; specimens were photographed by KDL using a Sony® 6000 digital camera attached to a Nikon® SMZ 800N binocular microscope and the figures were processed with Helicon Focus ® 8 stacking software and Adobe Photoshop CS5 to adjust the size and background.The distribution map for the two new species of Aulacocentrum was made using Paraview (https://paraview.org).
For terminology used in this paper, see van Achterberg (1993a), sculpture terms are based on Harris (1979), and vein terminology follows the modified Comstock-Needham system (van Achterberg 1993a).For a key to genera of Macrocentrinae in the Palaearctic region, see van Achterberg (1993b).For additional references and data, see Yu et al. (2016).Inside Vietnam, the distribution of the species follows the order of areas and provinces from north to south, and outside Vietnam, distribution of species follows an alphabetical order.
For the redescription of A. philippinense (Ashmead), see van Achterberg (1993b: 6-8) and figures therein; for the detailed descriptions of A. confusum and A. seticella, see He andvan Achterberg (1994: 160-163 andof A. nigrum Ku andPark, see Ku andPark (1997: 212-213), and figures therein.For the key in this paper, we used the comparative characters of A. philippinense and A. seticella of specimens collected in Vietnam.
In Vietnam, Aulacocentrum philippinense (Ashmead) was previously reported by Long and Belokobylskij (2003) as solitary parasitoid of the rice leaf folder, Cnaphalocrocis medinalis (Pyralidae).All the species found in Vietnam have morphological characters that fit well to Aulacocentrum in the key to genera and the diagnosis of this genus provided by van Achterberg (1993b), except A. glabrum sp.nov.: marginal cell distinctly narrower medially than basally and more or less broadly widened apically; first metasomal tergite elongate, flat basally or with medio-basal depression, 3-6× as long as its apical width; antenna of both sexes often bicoloured (a variable character in Aulacocentrum).
Male.Unknown.Biology.Unknown.Etymology.From assitus (Latin for "near"), because this new species is close to A. seticella van Achterberg & He, 1994, from China.
Male.Unknown.Biology.Unknown.Etymology.From glaber (Latin for hairless), referring to the hind wing with both the basal cell apically and the marginal cell basally glabrous.
Notes.This new species can be distinguished from other species by the following characters: marginal cell of hind wing largely glabrous basally, and vein 1-CU1 of fore wing quadrate.Description.Holotype, female, body length 9.8 mm, fore wing length 7.5 mm, ovipositor sheath 10.5 mm (Fig. 5).
Male.Unknown.Biology.Unknown.Etymology.From inter in Latin meaning "between", because this new species is intermediate between A. imparum sp.nov.and A. philippinense.
Male.Unknown.Biology.Unknown.Etymology.From simulo (Latin for "imitate, copy"), because this new species is similar to A. glabrum sp.nov.