The vertical and horizontal distribution, the flower visiting habits of adults and larval habits of Pidonia were investigated in the Oze-Okukinu range. This range is situated on the boundary between the Pacific Ocean side of Honshu which experiences summer rains and the Japan Sea side of Honshu which experiences snowfall in winter. The species assemblage of Pidonia in this range is discussed with reference to the biological surveys of Pidonia species in various parts of Japan from 1974 and studies of the dynamic vegetational changes since the Late Wurm Glacial period. A total of 24 species were collected on flowers from 27 to 31 July in 1993. Pidonia occurring in the cool-temperate deciduous forests were unevenly distributed on the Pacific Ocean side and the Japan Sea side of Honshu from one another. P. obscurior, P. insuturata, P. semiobscura, P. limbaticollis and P. oyamae occur in the Pacific Ocean side of Honshu, while P. hakusana, P. hayashii, P. miwai and P. takechii occur in restricted areas on the Japan Sea side of Honshu. Geographically allopatric pairs of phylogenetically related species, such as P. insuturata vs. P. hayashii, P. obscurior vs. P. hakusana occur in this range. Pidonia occurring in Oze visited mainly the flowers of arbores such as Cornus controversa and Acer caudatum ukurunduense. Pidonia occurring in Okukinu visited mainly the flowers of herbs such as Filipendula kamtschatica and Angelica polymorpha. Larvae of P. bouvieri fed on the bark of dead Abies mariesii in the subalpine zone of Mt. Hiuchi-ga-take on July 30, 1989. Larvae of P. chairo pupated directly in the bark of living Betula ermani in Hatomachi Pass on July 25, 1995. Eight examples of 11 pupal cells were found within 1 m above the ground and 3 examples were found from 1-2.8 m and below. Deep winter snows protect the larvae of Pidonia living in the bark of trees against dryness in the Japan Sea side of Honshu. The Pidonia fauna in the Oze-Okukinu range is the result of species expantion from the Pacific Ocean side of Honshu and from the Japan Sea side of Honshu, following the geographic movement of forests during the Postglacial Age.

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The biology of Paraxenos nagatomii, which parasitizes the multivoltine wasp, Bembicinus bimaculata, was studied at Haemida Beach, Iriomote Island (24°N) for 4 years (1995-1998). Two generations (previous and current) of the host always overlapped throughout a whole season. The percentage parasitism was much higher in the previous generation (23.4-91.7%) than in the current generation (12.1-44.1%), suggesting that parasitized hosts survived much longer than normal hosts. Several regularities of the parasitic position in host metasomas were recognized as follows : 1) Both male and female stylopids protrude his cephalotheca or her cephalothorax between 4-5 terga, when they mono-parasitize ; 2) Males tend to maintain the proper parasitic position (4-5) more often than females do, even in multiple parasitism ; and 3) Males prefer to protrude at 5-6 more than 3-4 in multiparasitization, while females do at 3-4 more than 5-6, reflecting the difference of abdominal length between sexes. The dominant stylopid, which developed faster than other stylopids in a host body, can choose 4-5 at protrusion. However, the orientation of stylopids in the host metasomas seems to be determined beforehand at early larval stages.

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Megachile subalbuta is mainly distributed in southern Japan and is partially bivoltine. The second generation emerged from those nests completed before late June. On alfalfa flowers, the speed of visitation was 12 flowers/minute and tripping rate was 100%, suggesting this species could be a promising pollinator of alfalfa. The maximum number of eggs laid per female reached up to 49, reflecting a high reproductive potential. Nest tubes, having diameter of 6.5-6.9 mm and length of approximately 15 cm, were most preferred. Various different types of leaf pieces were used for nest construction, i.e., large oval-shaped (A-1), small oval-shaped (A-2), and semiround-shaped (A-3) for the cell cup ; round (B-1) and semiround (B-2) for the cell cap. Semiround-shaped (C-1) was also used for closing the entrance. Moreover, the cell plugs, each was formed by 1-2 sheets of B-2, were pasted by partially masticated leaf fragments, and placed to close each provisioned cell. The last provisioned cell was protected by a double-layered cell plug. As natural enemies of M. subalbuta, Cylindrothecum, a phorid fly, Anthrax, Melittobia, Trogoderma, and Zonitis were found in trap-nests at several localities in southern Japan.

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Elodia flavipalpis (Aldrich) has been known as an endemic species in Japan, but its host has not been reported. We reared E. flavipalpis from Eudemis gyrotis (Meyrick) (Lepidoptera, Tortricidae) sampled from young leaves of bayberry, Myrica rubra Sieb. et Zucc., planted at Sasamagatake experimental area, Mt. Tanakami, Shiga Prefecture, Japan on the 20th of August, 1998.

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