In the course of the studies on Far-Eastern Tabanid-flies the writers found some species of this family were new to science. One new genus and six species of Tabanidae, two from Honshu, two from Kyushu, one from Shikoku and one from Ryukyu are here described. The writers express their hearty thanks to Dr. A. Yajima, Prof. T. Ishihara, Prof. R. Kano, Dr. N. Fukuhara, Dr. K. Ogata and Dr. A. Nagatomi who kindly lent precious specimens to the writers.

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In Korea, Dr. Harujiro Kobayashi and Dr. Katsushige Hori have classified Korean flies into 6 families, 17 genera and 45 species before World War II. Since then no further works on the family have been done in Korea. During the period from April of 1959 to September of 1960, Park had made an intensive collection of flies in the Taegu area which amounted to 4844 specimens of Sarcophagidae. A close examination of the specimens revealed that 3 species of Sarcophaga were new and 10 species were hitherto unreported from Korea. The authors will describe one of these new species in the present paper.

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In August, 1957, the writer made the investigation on the mosquito larvae in the 'Mosochiku' bamboo stumps, the split 'Mosochiku' bamboos and the 'Madake' bamboo stumps in and around Utsunomiya. 1. From the 'Mosochiku' stumps, 1, 050 larvae belonging to three genera and five species were collected. Of these, Aedes flavopictus was the largest in unmber, 53.4% of the total larvae, Tripteroides bambusa 33.7%, Armigeres subalbatus and Ae. albopictus was few, and Ae. japonicus was the least. 2. Many larvae were found in the split bamboos and 863 larvae blonging to three genera and four species were collected from three split 'Mosochiku' bamboos. Of these, Ae. flavopicus was the largest in number, 36.6% of the total. Ar. subalbatus followed it, and Ae. albopictus and Tr. bambusa were collected few. 3. The larval fauna of the mosquitoes in the 'Madake' bamboo stumps was poor, and the number of species and individuals was by far smaller than that in the 'Mosochiku' bamboo stumps. 4. 12 kinds and 86 larval associations were formed in the 'Mosochiku' stumps. Of these, Ae. flavopictus associations and Tr. bambusa-Ae. flavopictus associations were the largest in number. Seven kinds and 13 larval associations were formed in the split 'Mosochiku' bamboos. Of these, Ae. flavopictus-Ar. subalbatus associations and Ae. flavopictus-Ae. albopictus-Ar. subalbatus associations were the largest in number. Four kinds and 22 associations were formed in 'Madake' bamboo stumps. Of these, Ae. flavopictus-Ae. albopictus associations were the largest in number. 5. The phenomenon of "habitat segregation" between Ae. flavopictus and Ae. albopictus was not found out in the present investigation on the 'Mosochiku' stumps, the split 'Mosochiku' and the 'Madake' stumps just as in the previous reports.

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In late 1960 and early 1961, increased dosages and resprayings of diazinon failed to kill the house flies in several localities of Ibaragi and Chiba Prefectures. Collections were made subsequently, from ten of these localities in order to carry out a comparison with the normal Takatsuki or the resistant RP strain of houseflies. 1. As regards the development of resistance to diazinon the results of the experiments in the laboratory can be summarized as follows : On topical application, flies from Mihara in Hokota, Obata in Ibaragi and Hamajuku in Sodegaura showed an increased (LD)_<50> values, 10-20 times, that of Takatsuki strain. A 10-fold increase in resistance could be sufficient to invalidate organophosphorus compound as residual spray (as described by Keiding in 1956). At the 5 or 6th generation of further selection with diazinon these resistant flies in the laboratory had become 2 or 4 times as diazinon resistant as the populations originated. On the other hand the Hikone population, which was highly resistant to chlorinated hydrocarbons, gained only 2-fold tolerance to diazinon after 8 generations of diazinon-pressure. Hokota flies at the F_6 under diazinon-pressure showed resistance level about 100 times of the normal (Takatsuki) strain to diazinon. Houseflies taken early in 1961 from Kamigo district, Dejima Village in Ibaragi Prefecture, which had been treated with diazinon for one year, proved to be 4.7 times as resistant as the population in 1960. Another collection in 1960 from Sueyoshi district, Obitsu Village in Chiba Prefecture, which had been treated with diazinon during 1958-60, showed a 8-fold resistance. 2. The RP strain when kept in laboratory-showed no decrease of resistance even after 46 generations. Although flies taken from Hokota and Ibaragi and bred for five generations without further exposure to diazinon showed a slight fall in the levels of diazinon resistance, they were still considerably resistant to this insecticide. 3. These resistant houseflies showed resistance levels of from 10 to 20 times of the normal ones against diazinon, but only of 2-4 times of the normal to the other insecticides, i.e. DDVP, malathion, Nankor and Baytex.

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Surveys have been repeatedly conducted on rickettsia harbering rodents and medically important arthropods on three islands, Koshiki, Tane and Yaku, Kagoshima Prefecture, the most southern part of Japan, in May, 1959 and February, 1960. The results obtained so far in species and number of trombiculid mites and other medically important insects such as mosquitoes and flies are briefly summarized in the tables. This investigation was supported in part through a grant under contract No. DA-92-557-FEC 31, 515 between Dr. Takeo Tamiya and Offics of the Sugeon General U.S.A.

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