We have already outlined a fauna of the ectoparasites of Japanese wood mice (Matsuyama et Ueno, 1955, 1956) : in the present paper the fauna of ectoparasites of the wood mouse, Apodemus speciosus, the wild house mouse, Mus molossimus, and shrew-mole, Urotrichus talpoides, captured during the same survey from July 1954 to June 1955 was described. 1. Five shrew-moles were captured during a period between November 1954 and February 1955. A comparison of their ectoparasites with those of the wood mice captured during same period and the same place is as follows : Trombiculidae : Numerous T. kansai and a single T. kochiensis from shrew-moles. Nine species (containing T. kansai and T. kochiensis) in a considerable numbers of each species from wood mice. Laelaptidae : Only one individual of "Genus B" was collected from shrew-moles, whereas L. jettmari, H. japonicus, and E. stabularis from wood mice. Others : Cheyletidae sp. from shrew-moles, Ixodidae, Haematopinidae, and hypopus of Glycyphagidae from wood mice, each few in numbers. 2. Four wild house mice were captured during a period between Feburuary to April, 1955. A comparison of their ectoparasites with those of the wood mice captured during same period and the same place is as follows : Trombiculidae : From wild house mice, T. fuji, T. kitasatoi, T. daisen, T. kochiensis, T. pallida and T. miyajimai were collected, but T. kansai and G. saduski were not recognized. From wood mice all the species as above were collected. Laelaptidae : From wood mice, L. jettmari, H. japonicus, E. stabularis and "Genus B", whereas even not a single individual of Laelaptidae from wild house mice. Others : Except some hypopus of Glycyphagidae, no mite was found from wild house mice. From wood mice the mites of Ixodidae, hypopus of Glycyphagidae, Haematopinidae, and Cheyletidae were collected. 3. We believe that these differences of the ectoparasites fauna of these three host species due to the difference of the behaviour of each host, or the host selection of the parasites themselves.

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In the present paper, the authors report on the results of field studies on the control of malayan filariasis prevalent among the inhabitants of Hachijo-koshima Island which is located about 360km south of Tokyo. It has been known since old times that a kind of elephantiasis exists in this area, but it was 1951 that the causative parasite was identified as Wuchereria malayi (Brug, 1927) by the authors and their associates. Among the six species of mosquitoes found in this island, Aedes togoi was demonstrated to be naturally infected by the worm and acted as the main vector of the disease, and Culex pipiens pallens was also found to harbour the infective larvae of the parasite in experimental studies. The present study was designed to erradicate the disease from this area both by the treatment of human carriers and by the control of mosquito vectors. The projects started from August 5, 1956 with the examinations of thick blood smears of the inhabitans for the microfilariae. Out of 66 persons 22 or 33.3% were found to be positive. "Supatonin" (diethyl carbamazine compound) was administered to all of the carriers by the ratio of 6mg per kilogram of body weight daily for 14 days. Through previous studies, the drug was certified to be a very effective chemotherapeutic, but to cause febril attacks on the first few days of the course. As for the mosquito control, various measures were adopted simultaneously. DDT residual spray was applied to the total of 25 houses by the ratio of 2g of DDT to 1 square meter of the walls, using water suspension of 40% DDT paste manufactured by Nippon Soda Co. This immediately caused the practical erradication of adult mosquitoes and houseflies from the human dwellings. Breeding places of mosquito larvae were treated in different ways according to the types of water. Concrete rain-water reservoirs were the main source of the vector species, to which a kind of small fresh-water fish, Oryzias latipes (Temminck et Schlegel) carried from Tokyo or naturally bred at Hachijo Island was set free. Through previous experiments, the fish was found to erradicate mosquito larvae from the reservoirs. Miscellaneous water containers scattered in the village were treated by suspensions of DDT paste by the ratio of 1 ppm of DDT to the amount of water. Thousands of rockpools were also found to be scattered along the shore and to harbour large numbers of larvae of Aedes togoi. To this area, DDT dusting by a helicopter Bell-47-G was applied. A total of 180kg of 10% DDT powder was applied to an area of about 80, 000 sqare meters. All of the larvae examined after 24 hours were found to be killed by the insecticide. The island was again surveyed in December of the same year. The radical control of neither the parasite nor the vectors has not yet been attained. It was suggested that repeated applications of such control measures were needed to accomplish the purpose.

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The seasonal prevalence of fleas on Rattus rattus were studied at Fuchu, Tokyo, through consecutive 12 months, from March, 1955, to Feburuary, 1956. The fleas were Nosopsyllus fasciatus, Monopsyllus anisus and Leptopsylla segnis. Xenopsylla cheopis, Paradoxopsyllus curvispinus, Echidnophaga gallinacea and Tunga caecigea were not found during this survey. All the three species showed their top peak of prevalence in May 1955. The fleas are quite seldom during the summer season but after October the flea index gradually increases and showed a second peak in November. Therefore it seems that under the airtemperature between 10℃ and 20℃ the fleas may increase and decrease if the temperature ascend above 20℃.

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1. The results of the autopsy of mice and rats killed by one or continuous administrations also revealed the frequency of each haemorrhagic lesion observed in the order of lungs, stomach, intestines, heart, thoracic cavity, liver, abdominal cavity, brain, oral cavity, hypodermic lesions, reproductive organs, kidneys and pancreas. 2. The degree of pulmonary haemorrhage with continuous administrations of high dose was larger than the degree of pulmonary haemorrhage with one administration of high dose or continuous admistrations of low dose. 3. In the case the prothrombin time value was less than 300sec., the Benzidin reaction of feces was not always positive but that of urine was negative. In the case, however, the prothrombin time value was more than 300 sec., the Benzidin reaction of feces was positive in all tested mice but that of urine was negative in many mice. 4. In the first stage of warfarin poisoning within 24 hours after the first administration the haematocrit value and the number of erythrocytes increased in some degrees in parallel with prothrombin time value, but both decreased progressively in parallel with the number of administrations and the Benzidin reaction of feces rather than the prothrombin time value, and in the last stage of poisoning the haematocrit value showed about 50 percent (20-80 percent) of the normal value. 5. When haematocrit value became lower than 80 percent of the normal, erythrocyte sedimentation velocity of blood increased considerably independent to the prothrombin time value. But when haematocrit value was higher than 80 percent the normal haematocrit, erythrocyte sedimentation velosity of blood did not increase. 6. In the case the prothrombin time value was less than 300 sec., erythrocyte resistance against 0.3-0.5 percent of saline solution and 0.0001-0.1 percent of saponin was normal but when the prothrombin time value was more than 300 sec. a slight decrease of erythrocyte resistance was observed in some mice. The haemolytic action of warfarin was not observed in vitro. 7. In dependent to doses, leucocytes showed the fluctuation of two types as follows : 1) leucocytes of some mice decreased after the increase in the beginning 2) leucocytes of other mice decreased from the beginning of poisoning. And in the last stage of poisoning, leucocytes did not necessarily decrease less than normal value. Eosinophils fluctuated in parallel with prothrombin time value in the first stage of warfarin poisoning but in the last stage of poisoning, it decreased distinguishedly. 8. Blood plateletes showed similar fluctuations as that of leucocytes. 9. Pulmonary capillary resistance decreased distinctively in parallel with the prothrombin time value and the administered doses. And in the case the prothrombin time value was more than 300 sec., a remarkable decrease of pulmonary resistance was observed in the individuals which Benzidin reaction and decrease of erythrocytes were distinguished. In this pulmonary resistance test, capillary resistance of median lobe was most fragile. 10. Skin capillary resistance decreased in parallel with prothrombin time value. 11. Diffusion areas of india ink caused by hyaluronidase in the intracutaneous lesions of poisoned mice was larger than the untreated control.

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To evaluate the effectiveness of chemicals on the acaroid mites, two methods were devised and the effects of several miticides were tested. Ring method : A glass ring 9mm in diameter and 10mm in height was fixed with paste closely on a slide glass on which a piece of filter paper and black blotting paper labeled. In the ring, insecticidal suspension was dropped, and then about 100 mites were released. A cover glass was fixed on the ring with glycerine gelly. After 24 hours or 48 hours, the death rate of the mites was recorded. Petri-dish method : To test the contact effects of miticides, 300 to 500 mites were released on a piece of filter paper soaked with 2 cc of various dilutions of emulsion for 15 minutes. Then, the mites were transfered to anothor petri-dish, which was covered tightly by plastic sheat to prevent the escape of the mites. To test the fumigating effects of chemicals, a piece of filter paper treated by the chemical was hung by a string in deep petri-dish of 6cm in height and 8.5cm in diameter. This was designed to avoid the direct contact of the chemicals with the mites. After 24 hours, the results were recorded. The screening tests of 12 chemicals as the miticides on the acaroid mites, Tyrophagus dimidiatus, were carried out by the petri-dish method. The order of miticidal effect evaluated by the method was as follows; dieldrin>endrin>heptachlor>adrin>lindane, malathion, DDT>chlordane>diazinon>DN. The effects of o-dichlorobenzene and DDT were much lower than the above chemicals. Lindane was proved to be effective to the mites as the fumigant at room temperature (20℃) and as the contact poison, and was recommended in the practical use.

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The residual effects of DDT and dieldrin were observed in three stables and a chicken house in summer of 1956. Interior surface of pens was treated by DDT at the rate of 1g/m^2 or by dieldrin 0.1g/m^2, each three or four times from July to September. In the period the species of mosquitoes observed in the test areas were as follows : Aedes vexans nipponii, Anopheles hyrcanus sinensis, Culex tritaeniorhynchus, Aedes albopictus, Armigeres subalbatus and Culex pipiens pallens. The peaks of number of mosquitoes resting on the wall of the stables were 8.00 (A. vexans, C. tritaeniorhynchus) to 10.00p.m. (Anopheles hyrcanus sinensis) and 4.00a.m. (A. v., C. t., An. h. s., ). The mosquitoes resting on the wall in the night time were less in the treated stables than in the untreated ones. In the daytime, no mosquito was observed on the walls treated by the chemicals. But the residual effects of the chemicals observed seem to be lower than those estimated in laboratory.

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The effects of dieldrin emulsion to Sarcophaga peregrina were studied by treating them in larval stage, comparing with that of lindane emulsion. The mortalities of larvae after 24, 48 hours, and those in the total larval stage and in larval and pupal stages, were obtained by treating the 3 rd instar larvae through the rice-husks immersion method, thus obtaining the retarded lethal effect of the chemicals. The lethal efficacy of concentration-mortality regression equation was lower in dieldrin than in that of lindane. The ratio of LC-50 of dieldrin to that of lindance were 1.6 for the larval mortality after 24 hours, 1.9 for after 48 hours, 2.0 for the mortality in total larval stage, and 9.7 for that in larval and pupal stages, so that it was concluded that the retarded lethal effect of dieldrin was higher than that of lindane. It was also recognized that the application of dieldrin or lindane to the larvae would tend to promote their emerging time, though the degree of the promotion was not so remarkable. The number of the flies emerged in the night time was greater than in the daytime, both in the treated and in the untreated by the chemical.

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Dieldrin solution with different solvent was dropped on house flies by a microsyringe, and the insecticidal effects were compared with each other. It was recognized that there exsisted significant difference among the insecticidal efficacy of those solutions, and also exsisted positive corelation between the boiling points of the solvents and the insecticidal efficacy of the solutions.

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The eradication of the cockroaches established in the ships sailing home and abroad is a great concern for the sanitary officers. The result of a survey practised for about two years at Kobe herbour, of the species of the cockroaches taken from 28 steamboats was presented in this paper. The material, each a small example of cockroaches collected by fumigation has been sent for identification to our laboratory. The most prevailing species was the German roach, Blattella germanica, being found in 23 ships; the other two species, the American roach, Periplaneta americana, and our common black roach, P. fuliginosa were taken in five and four cases respectively.

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