Abstract:

The present paper deals with the survey and taxonomic study of egg parasitic wasps of larch caterpillar, Dendrolimus superans sibiricus Tschetv., in Daxinganling Mts. forests. Totally 5 wasp species were reared with 54.63(± 1.70) percent of the pest eggs were parasitized by them. It was showed that the egg parasitic wasps played a very important role in reducing the pest population in the Mts. forests. The 5 species, including a new pteromalid, are as follows.1. Proctotrupoidea 1) Telenomus tetratomus Thomson (Figs 1-4) (Scelionidae)Chalcidoidea 2) Pachyneuron solitarium (Hartig) (Figs 5 - 8) (Pteromalidae)3) Mesopolobus superansi Yang et Gu, sp. nov. (Figs 9-13) (Pteromalidae)4) Ooencyrtus pinicolus (Matsumura) (Figs 14-16) (Encyrtidae)5) Trichogramma dendrolimi Matsumura (Figs 17-19) (Trichogrammatidae)Mesopolobus superansi Yang et Gu, sp. nov. (Figs 9-13)Female: 1.9-2.2mm long. Blue-green with metallic lustre; gaster with posterior margin of tergite 1 to end purple-brown; antenna and legs having all segments except coxae stain-yellow with slight brown; wings hyaline.Head and thorax densely raised-reticulate. Head without occipital carina, the broadth 2.2 times as its length in dorsal view, 1.25 times as its height in facial view, and wider than thorax and gaster (50:42:46); POL 1.8 times as long as OOL; lateral ocellus separated from eye margin by 2.3 times its oblong diameter; toruli ovate in shape, separated from each other only by 1/2of their own width; clypeal margin slightly excised, about 0.23 times of the head width; scrobes shallow. Antenna (Fig. 10) 13-segmented with 3 anelli.Thorax wide and flat; pronotum with collar in middle part of anterior margine carinate; notauli not deep, but reaching 3/5 length of the mesoscutum; length of mesoscutum only 0.6 times of its width: scutellum longer than wide (26:22), and as long as mesoscutum. Propodeum (Fig. 13) with plicae and without median carina, in its median area having weak keels growing from anterior margin and extending posterio-laterally, and in its lateral parts reticulate. Forewing (Fig. 12) with marginal vein about 1.6 times of stigmal vein. Gaster (Fig. 13) as long as head and thorax combined, conic-ovate and pointed towards the tip.Male: 1.6--1.8mm long. Resembles female, but colour of body much brighter, with golden-green lustre; posterior half of gaster tergite 1 orange -yellow, and the other tergites purple-brown; antenna (Fig. 11) with scape and funicle 4 and 5 white, the other segments stain-yellow and basal part of club brown; on stigmal vein of forewing with a small fumeus spot; gaster shorter than head plus thorax.The new species is close to the Japanese M. tabatae (Ishii), 1938, which is an egg parasitoid of Dendrolimus albolineatus Matsumura, but can be distinguished by the key below:1 Body 1.9-2.2mm long: head only slightly wider than thorax (50:42);the lateral ocellus separated from eye margin by 2.3 times its own oblong diameter; toruli separated each other by 1/2 of their own width; scutellum longer than wide (26:22); propodeum without median carina; marginal vein of forewing only l.6 times of stigmal vein……………… Mesopolobus superansi sp. nov.2 Body 3.1mm long; head much wider than thorax (50:32); the lateral ocellus separated from eye margin only by its own diameter; toruli separated each other by their own width; scutellum as long as wide; propodeum having median carina; marginal vein of forewing 2 times of stigmal vein…………Mesopolobus tabatae (Ishii)

Key words: Dendrolimus superans sibiricus T., Egg parasitic Wasps, Hymenoptera, Serphoidea, Chaecidoidea, Bionomics, Mesopolobus, New species