Bethylidae is the largest family of Chrysidoidea (Hymenoptera: Aculeata) and distributed widely from the tropics to the subarctic regions around the world. Most members of the family are relatively small, and are generally known as ectoparasitoids of immature stages of Lepidoptera and Coleoptera. Some species have been used and studied as natural enemies of various insect pests in some countries. Even though the family Bethylidae is important group as natural enemies in the agricultural and forestry fields, fundamental researches on this group such as a faunal study have not carried out and poorly known in Korea. Since 2005, we have carried out the faunal investigation of Korean Bethylidae and more than 1,600 specimens were collected by 2010, with some of their host insects. As results of present study, fifty two species belongs to sixteen genera of Bethylidae are recognized in Korea, including seven previously recorded species as of 2006. We will introduce on the biodiversity of Korean Bethylidae and its applied aspects as potential biocontrol agents against various insect pests with cases of their usages.

The genus Oberea belongs to the tribe Saperdini (Coleoptera: Cerambycidae) and contains about 270 described species in the world. The genus can be defined by the combination of the following characters: body elongate, cylindrical; legs very short, apex of hind femur not reaching beyond abdominal sternite II. O. vittata Blessig was reconfirmed its distribution in South Korea during the study. Two species are newly reported here: O. heyrovskyi Pic and O. tsuyukii Takashi & Ohbayashi. We provide a revised checklist of 12 species and a pictorial key to species for the identification, with diagnostic characters of O. heyrovskyi and O. tsuyukii.

As an natural enemy against the Monochamus alternatus Hope and M. saltuarius Gebler (Coleoptera: Cerambycidae), the vector species of the pine wood nematode (Bursaphelenchus xylophilus (Steiner & Buhrer), Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is recognized for the first time in Korea. The family Bothrideridae is also reported for the first time in Korea. We provide the diagnosis, illustrations, biological information, and the host insects of D. helophoroides (Fairmaire).

Goniozus Förster which is belonging to the subfamily Bethylinae (Hymenoptera: Bethylidae), are one of the large genera, and consist of approximately 170 species worldwide. Most members of Goniozus are ectoparasitoids of immature stages of microlepidopteran families, mainly Gelechiidae, Pyralidae and Tortricidae. As a results of this study, a total of five species of the genus Goniozus are recognized in Korea, which includes two new species, two newly recorded species and a previously recorded species. Diagnosis and illustrations for each species are presented.

Up to days, 15 species of the genus Xylotrechus, which have most diverse species among the tribe Clytini, have been recorded from Korean peninsula. The genus Xylotrechus can be distinguished from the other genera by combination of following characteristics: length of antennal socket longer than 1st segment of antenna; antennae reaches about 2/3 of elytra or less; carinae on frons well developed; 1st segment of hind tarsus 2 times longer than total length of 2nd+3rd segment; carinae on frons exceeding vertex; compound eye joined prothorax. In 2007, we collected a specimen which is belong to the genus Xylotrechus from Goyang-si, Gyeonggi province and we identified this specimen with Xylotrechus pavlovskii Plavilstshikov. Xylotrechus pavlovskii Plavilstshikov is easily distinguished from the congeneric species by following characteristics: femora black except basal half pale brown; antennal socket with yellow pubescence patch; pronotum black with distinct six yellow pubescence patches; elytra black with four pairs of yellowish linear pubescence patches except anterior 1/5 part reddish, apice blunt with inner and outer small sharpen projection. As a result of this study, we report this species for the first time from Korea with description and illustrations of diagnostic characters.

Six species of the Pristocerinae are recognized from Korea, including two new species (Pseudisobrachium sp. nov., Parascleroderma sp. nov.), and four species new to Korea (Acrepyris minutus (Yasumatsu 1955), Apenesia elegans Terayama 1999, A. okinawensis Terayama 1999, and Pristocera formosana Miwa et Sonan 1935). The illustrations of diagnostic characters are presented with a key to species of Korean Pristocerinae is provided.

Odontepyris sp. nov., a new ectoparasitoid on the caterpillar of Telorta divergens (Butler, 1879) (Lepidoptera: Noctuidae), is recognized from Korea. After rearing the larvae on the host insect, adult females were obtained and described. Revising all known species of genus Odontepyris, a key to the species of the genus Odontepyris is presented for the Eastern Palearctic region.