Hitherto, 37 species in 10 genera under 4 subfamilies have been known from the Korean Peninsula. In this study, three newly recorded species are reported for the first time from Korea: Conops ceriaeformis ussuriensis Zimina, 1974, Physocephala pielina Chen, 1939, and Myopa picta Panzer, 1797. Morphological diagnoses and illustrations of these species are presented. Additionally, a key to all species of Conopidae from Korea is also provided.

The genus Argyresthia Hübner, [1825] of the family Argyresthiidae is known to comprise over 150 species worldwide. Among them, more than 70 species are recognized in the Palearctic region. The Korean fauna of the genus Argyresthia includes 11 described species to date. In this study, we report three species of the genus Argyresthia for the first time in Korea: A. brockeella (Hübner, [1813]), A. longalbella Liu, Wang & Li, 2017, and A. mala Liu, Wang & Li, 2017. All available information, images of adults and genitalia for species are provided.

This study reports the first records of four coleophorids, namely Coleophora kamchatica (Anikin, 1999), C. lativittella Erschoff, 1877, C. levantis Baldizzone & Oku, 1988, and C. citrarga Meyrick, 1934, in Korea. Additionally, the presence of two species, C. montaniella Oku & Kusunoki, 2018, and C. artemisicolella Bruand, 1855, in Korea has been overlooked in the previous checklist of the family Coleophoridae in Korea, despite there being evidence of their existence. Consequently, with these additions, the total number of known species in Korea has been confirmed to be 42, expanding from the previously identified 36 species. Diagnostic characteristics and photographs of adults and genitalia for the four newly recorded species are provided, along with evidence supporting the presence of the two overlooked species in Korea.

The genus Paragabara is recognized as a member of the subfamily Boletobiinae, with six species in the Eastern Palaearctic. In Korea, three species of this genus are known. Konoenko et al. (2010) designated a lectotype for P. flavomacula (Oberthür, 1880) and described a new species, P. curvicornuta. In this study, the misidentification of the Korean P. flavomacula as P. curvicornuta has been corrected. Additionally, one newly recorded species, P. curvicornuta, is reported from Korea. In total, four Paragabara species are recognized in Korea. All available information, images of adults, a checklist, and male and female genitalia, etc., are provided.

Henricia specimens were collected using a dual approach of trimix scuba diving and fishing nets. This inclusive collection encompasses the discovery of two species highlighted in this study and introduces and provides comprehensive descriptions for Henricia kinkasana and Henricia longispina aleutica. The descriptions offered in this study were derived from the thorough examinations of external morphological characteristics. The documentation provides detailed insight into key traits related to the abactinal and actinal skeletons and spines of these newly recorded species in Korea. This comprehensive examination contributes to our understanding of the distinct morphological characteristics defining each species within the genus Henricia.

한국산 Autosticha kyotensis (Matsumura, 1931) (교토점원뿔나방, 신칭)이 새롭게 추가되었다. 이 종에 대한 성충과 생식기 형태에 대한 사 진 정보와 Autosticha속의 전 세계 체크리스트가 함께 제공되었다.

Three free-living marine nematodes (Desmoscolex (Desmoscolex) max Timm, 1970, Daptonema longiapophysis Huang and Zhang, 2010, and Pseudosteineria sinica Huang and Li, 2010) were newly recorded in Korea. Desmoscolex (D.) max was found from subtidal coarse sediment around Wangdolcho in the East Sea. It was characterized by the presence of untypical setae arrangement, obviously elongated triangle-shaped head, long hairy cephalic setae, a long naked tail spinneret, and the absence of peduncle at the base of somatic setae. Daptonema longiapophysis was obtained from intertidal sandy sediments in the southern coast of Korea. It was characterized by the presence of setiform labial sensilla, spicules with a projection on both sides, and gubernaculum with dorso-caudal apophysis. Pseudosteineria sinica was discovered from the intertidal sediment in the Yellow Sea. It was characterized by unobservable amphideal fovea, different lengths of spicules, and gubernaculum with dorso-caudal apophysis. In this study, we provide detailed morphological features of three free-living marine nematodes by differential interference contrast microscopy.