Two new genera, Sernokorba gen, nov. and Hitobia gen. nov., are described in the family Gnaphosidae. Three species are transferred to the new genera and redescribed; Sernokorba pallidipatellis (BÖSENBERG et STRAND, 1906), comb. nov., from Zelotes, Hitobia unifascigera (BÖSENBERG et STRAND, 1906), comb. nov., from Poecilochroa and H. asiatica (BÖSENBERG et STRAND, 1906), comb. nov., from Berlandina. A new species is described from Japan under the name Hitobia yasunosukei. The male of Hitobia asiatica is described for the first time.

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Three species of the genus Agroeca are reported from Japan: A. montana HAYASHI, 1986, A. coreana NAMKUNG, 1989, and A. kamurai sp. nov. Key to the Japanese species of the genus Agroeca is also given.

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Two species of the spider genus Euryopis belonging to the family Theridiidae are reported from Japan. A cosmopolitan species, Euryopis taczanowskii KEYSERLING, 1886, is recorded for the first time from Japan, and a new species, E. iharai sp. nov., is described.

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Size composition of prey by number and feeding time was estimated in the orb-web spider Nephila clavata by means of video recordings and sight-count censuses. Small prey (_??_2mm in body length) constituted more than 80% by number and nearly 30% of feeding time. Distributions of prey size in terms of feeding time were similar between the two methods. Considerable variation in feeding time was found among individuals, but the small prey were eaten relatively constant. The significance of small prey and reasons for wide range utilization of prey size in web-building spiders are discussed.

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A Japanese species of tea rust mite so far regarded as Acaphylla theae (WATT) or A. steinwedeni KEIFER is described under the name A. theavagrans sp. nov.

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A Korean clubionid spider, Clubiona kasanensis PAIK, 1990, is newly recorded from Tokushima Prefecture, Japan. Its systematic position in the species group of Clubiona corticalis is discussed. The male palp is illustrated on the basis of the Japanese material.

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Two species, Enoplognatha submargarita sp. nov., and Enoplognatha margarita YAGINUMA, 1964 are reported from Xinjiang Uygur Autonomous Region, China. The latter species is recorded from China for the first time.

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Japanese spiders of the genus Metleucauge LEVI, 1980 are revised. Two known species, M. yunohamensis (BÖSENBERG et STRAND, 1906) and M. kompirensis (BÖSENBERG et STRAND, 1906) are redescribed. Two new species are described under the names M. yaginumai and M. chikunii.

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Development and web growth of Atypus karschi were investigated by means of individual rearings under semi-outdoor conditions. Males required 3 years for development from egg to adulthood, passing through 8-9 molts after emerging from the maternal web. Females also developed to adults in 3-4 years with a variable post-emergent molt number from 9 to 11. The mean web width increased from 2.3mm to 13.3mm in males and 13.7mm in females during the period of nymphal development. In the case of adult females, however, web width continued to grow up to 15.9mm or more, since they lived for 3 or more years and repeated a post-adult molt every year. From the examination of seasonal change in weekly excretion frequencies through one year, it was observed that adults and nymphs were still active even in winter. The life cycle of this species is described based on these results and field observations.

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Two new species of the spider genus Clubiona LATREILLE, 1804, are described from Kanagawa Prefecture, Honshu, Japan, under the names C. ikedai and C. kumadaorum. The former new species belongs to the species-group of Clubiona obesa (subgroup of C. akagiensis) and resembles C. chikunii HAYASHI, 1986, while the latter seems to be a member of the species-group of C. pallidula (subgroup of C. propinqua) and closely related to C. maya HAYASHI et YOSHIDA, 1991.

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Two new species of the spider genus Philoponella (Uloboridae) are described from Taiwan and Borneo, South East Asia, under the names, Philoponella nigromaculata (Taiwan) and P. sabah (Borneo).

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The male of Cyclosa onoi TANIKAWA, 1992 is described for the first time based on the specimens colletced from Tokyo and Hyogo, Japan.

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Some halacarid specimens from the North Sea and the NEWELL's collection, usually known under the name Anomalohalacarus anomalus (TROUESSART, 1894), are re-examined. The material from the North Sea is identified as A. anomalus, and some taxonomic characters of A. anomalus are emended based on this material. NEWELL's specimens should be referred to A. tenellus BARTSCH, 1979 and A. tenuis BARTSCH, 1979, on the basis of the leg and palpal chaetotaxies.

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Callitrichia formosana OI, 1977 is newly recorded from Japan, based on the specimens collected from Iriomotejima Island, Okinawa Pref. It was described by OI (1977) under the genus Callitrichia which was synonymized with Atypena by JOCQUÉ (1983). This synonymy is accepted and Atypena formosana, comb. nov. is proposed.

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To estimate instar of Linyphia emphana WALCKENAER, the relationships between body sizes and instars were investigated under three different feeding conditions by rearing in plastic cases. Three body size parameters of each instar of the rearing spiders, i.e., posterior width of median ocular area, width of eye area, and width of carapace, were measured. Of these, the posterior width of median ocular area steadily increased 0.03mm (range 0.02mm) after each ecdysis, while other body sizes were remarkably varied. The result of this study shows that posterior width of median ocular area was the best indicator to estimate the instars of this species.

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