Difference of the locomotion of Trimeresurus flavoviridis was found between facing to man and isolated from man. Facing to man, the snake made striking pose on its position or rapidly escaped meandering its body. On the other hand, the isolated snake, having loosed its striking pose in a certain period of time, started to move slowly and wandered not in the meandering way. The latter locomotion, having hardly been perceived hitherto, was considered to be one of the aspects of the behavior in the natural environment. 2) The advancing speed of Trimeresurus spat wandering locomotion was measured from the time while a part of a snake continuously passed through a distance of 30cm. Little significant difference of the speed was seen among different individuals of the snakes nor among different intensities of illuminations from 2 to 2300 luxes and the average speed was 114.8cm/min. at 20℃. 3) The advancing speed of the snakes which were used in the experiments on the previous day was slower, 70cm/min. at 20℃. in average and above prolongation seems to be caused by being exhausted or tamed. 4) When the snake was placed 136cm. distant from a dark place, it reached there wandering and resting on the way. From the time required for passing this distance, the velocity was measured as a vector speed wholly. The vector velocity, differing at each intensity of illuminations, measured 49.6cm/min., 111.5cm/min. and 138.8cm/min. at 2, 100 and 2000 luxes respectively. The results showed that the snake wandered along a long way round and frequently rested when in the dark place. This locomotion has been thought to be one of the aspects of the behavior in the natural environment and could be seen in laboratory when in the dark and being isolated from man. 5) Persistent time of the striking pose after isolation has been not considered to be influenced by the intensity of illumination. But it seemed to be prolonged when the snake was active and wild. And the duration of the pose could be recognized as a sign of the wildness.

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Although the green bottle fly, Phormia regina belonging family Calliphoridae is well known as a common species in Hokkaido, Japan; the occurrence of the fly in Honshu of Japan is almost unknown but with some exceptions : Only the one male collection from Morioka in Iwate Prefecture by K. Hori (1950), the five male collection from Naoetsu in Niigata Prefecture by Y. Saito (1955), collections of this fly from Tohoku District excluding Miyagi and Fukushima Prefectures by R. Kano and S. Shinonaga (1963), and the seventeen males and one female from Kanazawa City by H. Kurahashi (1964). Some weeks after the great earthquake in northwestern Japan which happened on 16 June 1964, and being called 'Niigata-Earthquake', the insecticide-spraying by helicopters against both mosquitoes and flies of medical importance was carried out early in the next month July. In the course of this practice, accidentally it was noticed that the occurrence of a relatively large number of Ph. regina was demonstrated in the fly-collections from Niigata City. In view of the fact, further investigations of fly fauna and particularly of Ph. regina were undertaken in several localities in Niigata Prefecture and compared with the earlier data which had already been obtained by the present authors from the same prefecture during the past several years. The results obtained are as follows : The total number of flies collected from 9 localities (Niigata, Shibata, Maki, Tochio, Nagaoka, Tokamachi, Naoetsu, Ryotsu and Aikawa) during from July to September 1964, were 49, 568 consisting of various genera and species of family Muscidae, Anthomyiidae, Calliphoridae and Sarcophagidae. Of totaled 49, 568, 4, 450 (9.0%), and of totaled 41, 008 specimens of Calliphoridae, 4, 450 (10.8%) were the members of Ph. regina respectively. The flies collected from Niigata City only during the same months were 45, 463 in total number, in which 9.7% of the whole flies and 11.7% of the flies of Calliphoridae were occupied by the members of Ph. regina respectively. In Ph. regina, male by female ratio was almost equall (47.1 : 52.9) based on the 2, 862 specimens trapped in Niigata City during the summer months. As to diurnal and seasonal activities of Ph. regina, it was found that this fly was most active at lighter and hotter daytime in summer though actually active from late April through summer to mid-November. In the other hand, the flies collected from Niigata City from April to December 1963, were 8, 954 in total, of which 5, 876 (65.6%) were the flies of Calliphoridae and 0.7% of the same family were Ph. regina. In 1955, the flies collected from 19 localities in Niigata Prefecture during from April to December were 30, 751 in total number and only 5 male specimens of Ph. regina were found in them. On the basis of those yearly observations, it was newly known that recently Ph. regina showed a tendency to increase in population year by year in Niigata Prefecture, Honshu, Japan.

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It has been seemed that housefly (Musca domestica vicina) is generally bred from fresh rearing sources for its larva, and not from rotten sources. Yet, the information about the relation between the state of medium and the breeding of housefly has been quite scarce. In this experiment, and artificial medium for housefly was used and tested to make clear that housefly could be bred from the medium or not. The material of artificial medium was so-called "dry mixed feed for rat and mouse" which includes corn meal, rice-bran, fish meal, dry yeast, soy-bean meal, cod-liver oil, salt and calcium, etc. The medium was treated with the combination of following three factors. Temperature was kept at three grades of temperature 10°, 30°, and 50℃, while lapsed time after the preparation of medium had 1, 3, 5 days and 1, 2, 3, 4, 6, 8 weeks, and then, the top of the pot with medium was covered by cotton or vinyl cloths which were called "opened or closed condition", respectively. The control medium used the same material of just after the preparation. The breeding of housefly was observed in such treated or untreated media. And then, to know the state of treated media, we have measured total nitrogen by Kjeldhl method, pH by pH meter, and acid value by N/10 NaOH, in the media. The results were summarized as follows : (1) The breeding of housefly varied according to the treated conditions of media. Especially, it was influenced by the temperature conditions. In the case of the media kept at 10℃ with lapsed time from 1 to 8 weeks, the breeding of housefly was similar with the case of control medium. And in the media treated at 30℃ in opened condition, housefly was fairly bred regardless of the lapsed time. Housefly, however, could not be bred on such media that were treated at 30℃ in closed condition and 50℃ in the cases of both opened and closed conditions, regardless of the lapsed time. (2) Total nitrogen, pH and acid value were measured with the treated media and it was seemed that total nitrogen of every treated media showed little difference and it has slightly upward tendency according to the lapsed of time. On the other hand, pH and acid value of the media changed according to the treated condition of media. For example, in cases of 10° or 30℃ in opened condition, they had no great difference, but in the closed condition of 30℃ and in the condition of 50℃, pH of the media decreased and acid value of them increased, as compared with the control medium. (3) The breeding of housefly was seriously affected by the state of treated media, especially, pH and acid value of media. When the state of medium indicated less than 5.5 of pH and more than 100 of acid value, housefly was not bred at all. It is supposed that the limit of breeding of housefly will be approximately around the point where pH is 5.5 and acid value is 100, in the medium.

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An investigation of bovine thelaziasis and its vector was conducted by the authors in Niikappu Pasture, Hokkaido, during the period August, 1962- November, 1963. The results are as follows : 1. The flies found on cows were mainly Musca convexifrons, Morellia simplicissima, Stomoxys calcitrans and a few other species. Of these, M. convexifrons and M. simplicissima gathered around the eyes of cows and licked their tears. 2. Although 3, 923 specimens representing several species of flies were dissected, thelazian larvae were found only in females of M. convexifrons. 3. Thelazian larvae were found in females of M. convexifrons from July to October. The highest percentage of infected M. convexifrons was found in October, although the number of thelazian larvae per individual fly was greatest in September. 4. Females of M. convexifrons were dissected into four parts (proboscis, head, thorax, and abdomen). Each part was examined separately for presence of thelazian larvae. In these examinations, thelazian larvae were found most frequently and in greatest number in the abdomen. The head was second in this respect. 5. Infection rate showed a direct correlation with ovarian development in M. convexifrons. The highest infection rate was found among flies with fully developed ovaries. 6. Thelazian larvae were collected from eyes of cows throughout the year. The infection rate was highest from September to November, and lowest during May and June. 7. All adults of Thelazia collected from eyes of cows were identified as Thelazia rhodesi (Desmarest, 1827).

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The following is presented as the summary of the findings of the present investigations : The probable importance of the common flies in the transmission of bacillary dysentery and diarrheal disorders should still not be underestimated in the not so sanitary areas. Especially the prevalence of Morganella spp. in and on the fly body, some members of which might be the causative agents of summer diarrhea, would be regarded as the presumptive index of sanitary condition of the area under investigation. Therefore, corresponding attention should be directed to fly control.

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Two field surveys were carried out in filariasis endemic areas in order to assess the relationship between ages of mosquitoes and their infection with various stages of developing filarial larvae. One survey was done in Okino Erabu Island, in the southwestern part of this country, where bancroftian filariasis has been endemic with a microfilaraemia rate of about 10% among the inhabitants. Here Culex pipiens fatigans is the only certain vector. Another survey was carried out in Hachijo-Koshima Island, a small islet some 250km south of Tokyo in the Pacific Ocean. This is the only site of malayan filariasis so far known in Japan with a microfilaraemia rate of 19% among inhabitants at the time of our examination, Aedes togoi is the only vector. In both islands female mosquitoes were collected inside houses from 20 to 22 hours nightly by using sucking tubes and were dissected on the following morning. First the ovary was isolated and the physiological age of the individual mosquito was determined by observing the number of relics at pedicel of the ovariole, according to Detinova's method (1962). The whole body was then dissected out and examined for filarial larvae. Among 349 dissected mosquitoes of C. pipiens fatigans, which were caught resting indoor at Okino Erabu Island in May, 1963, 50.7% were nulliparous, 39.70% uniparous, 8.65% biparous and 0.89% triparous. Of these 45.2% were found to have fed. Although 8.8% were infected, the infective rate was 0.29%. It is of interest to note that the infected rate increased with an increase of age of the mosquitoes : i. e., 7.06% were infected among nulliparous, 9.77% among uniparous, 10.34% among biparous and 66.7% among triparous. This naturally follows, since the older mosquitoes have had more opportunities to take infective bloodmeals. The nulliparous mosquitoes also were often found to be infected; however, all larvae were in the early phase of development. And most noteworthy is the fact that the mature infective larvae were found only in the biparous and older mosquitoes. This suggests that the age composition of the population, particularly the relative proportion of biparous and older groups is of prime importance as a factor to be considered in connection with the transmission of the infection to man. The results obtained with Aedes togoi in Hachijo-Koshima Island in August, 1963 showed the same trend as that described above. Among 108 mosquitoes dissected, 43.3% were nulliparous, 46.3% uniparous, 9.3% biparous and 0.93% triparous. Of these, 77.8% had fed, 6.48% were infected, and 1.85% were infective. The rate of infected mosquitoes was 2.13% among nulliparous, 6.0% among uniparous, and 33% among biparous. The infective larvae could be detected only in the biparous mosquitoes. In both areas the rate of infected mosquitoes was higher among those collected from houses where microfilarial carriers dwelt, than among those collected from houses of non-carriers. However, the infective rate was no different among mosquitoes in either carriers' houses or those of non-carrieres. Since the mosquitoes could have moved around for a considerable distance by the time ingested microfilariae reached the mature stage, it is reasonable to find infective mosquitoes in either kind of house. Hence it is recognized that any of the inhabitants of the area were exposed to the same risk of infection in their respective areas. In both endemic areas no significant trends to familial aggregation of infected cases were observed.

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1. Mutant strains which exhibit "green" (Gr) and "orange" (Or) pigmentations at the 4th instar lavae were isolated from a colony of the autogenous form of the common house mosquito, Culex pipiens molestus. After selective breedings of such mutants for 4 generations, both Gr and Or could be established almost to the true breeding line strains, but the reverse selections for establishing white (Wh) strains which completely lack in such colour characters were rather difficult and the larvae at the generation were still ununiform in their coloration. 2. Crossing experiments were made on both sides with Gr and Or males and females. All the larvae at F1 generation were intermediate (Mix) in colour character. At F2 generation the larval colorations could be classified into Gr, Or, Mix and Ye by the ratios of roughly 12, 18, 67 and 3 percent respectively, in which a new character Ye appeared which could be differentiated by "yellow" coloration of the larvae. The adults reared from Ye were all males. 3. At the crossing between Ye males and Gr females, F1 larvae were all Gr and F2 were separated into the classes by ratios Gr 53%, Or 21% and Ye 26%, while F1 larvae obtained by the cross between Ye males and Or females were all Or and F2 were roughly Or 88% and Ye 12%. All of the adults reared from Ye were also the males, and the percentages of Gr females plus Ye males were always almost equal to that of Or females in all of these experiments. 4. The above genetical characters of Gr and Or are at most polygenetical in nature, and further genetical and biochemical studies need before these larval colour characteristics could fully be elucidated. 5. The above genetical characters were found to be useful markers in many ways in the researches on this species of the mosquito. As an example, the insecticides susceptibility of the non-selected parent colony and the Gr and Or strains were compared with DDT, dieldrin, lindane, fenthion, malathion, ronnel, dichlorvos, diazinon and Sumithion as the test insecticides, there are no significant differences could be detected. There seemed to exist no correlation between the above mentioned larval colour characters and the resistance to those insecticides.

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The differences of residual effectiveness of insecticides applied to different surfaces were studied using DDVP, diazinon, ronnel, lindane, malathion, Sumithion, Baytex, dieldrin and p, p'-DDT. These were applied in ethanol solution to glass plate and filter paper. Their effects were evaluated in laboratory tests using the adult houseflies, Musca domestica vicina, and the house mosquito, Culex pipiens pallens. All the insecticides, except DDVP, applied to the glass plate were more effective than those applied to the filter paper, when the insects were brought into contact within 24 hours after the application. The effect of the more volatile DDVP was reduced rapidly because of the high initial loss of the toxicant on the glass plate; therefore the mortality observed on the glass plate was lower than that observed on the filter paper 8 to 24 hours after the application. In general, it has been found that insecticides having the steeper slopes of the ld-p line produce larger differences of LC_<-50>'s between the glass plate and the filter paper when compared immediately after application. In residual effects highly volatile chemical, for example DDVP, showed higher mortalities on the filter paper in comparison to the glass plate, and the differences of LC_<-50>'s between the latter and the former became greater as time elapsed. Although moderately volatile insecticides such as diazinon, ronnel and lindane, applied to the glass plate gave higher mortalities for a few days, their LC_<-50>'s obtained from 4 to 8 days after the application were almost equal on both types of treated surfaces. After 8 days higher mortalities were observed on the filter paper than on the glass plate, the differences of LC_<-50>'s increasing in accordance with the time elapsed. The effects of residues from insecticides with low volatility, i. e. malathion, Sumithion, Baytex, were higher on the glass plate during most of the 64 days test period, although the differences of LC_<-50>'s were reduced as age of the residues increased. Throughout the entire test period of 64 days, insecticides of low volatility, dieldrin and DDT, showed high mortalities when applied to the glass plate; those effects, or the differences of LC_<-50>'s were almost the same on both surfaces as those obtained initially after the application. In interpreting these experiments, it is considered that the adsorption of solutions containing toxicants on or into the treated surface, the release of toxicants into the air by evaporation, and the translocation of toxicants from treated surface to untreated, were the factors affecting the differences in residual effects of insecticides applied to different surfaces as residual sprayings.

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Experiments were made to estimate the effects of insecticide applications on the population densities of the adults of Culex pipiens fatigans in four areas in Bangkok. The insecticide used was 10% Sumithion emulsion, and the population densities were measured with the box-trap method newly developed for this purpose. In area T where residual sprays to all houses with the ratio of 50ml of 0.5% solution per square meter of the wall surface, the reduction of the mosquito density was seen immediately after the sprays to about 13%, and recovered to about 50% on a month later when the second spray was applied. The population level dropped to about 6% at an observation made 6 weeks after start of the spray. In area W, no residual spray was made but all the breeding places of the larvae were treated by spraying Sumithion emulsion at the rate of 0.1ppm, at weekly intervals. The. reductions in the adult populations were seen only after a few weeks from the start of the treatments, but the effects were remarkable and the populations were kept at levels below 10% so long as the weekly sprays were continued. Simultaneous applications of the adult control by residual house sprays and the larval control by the treatment of breeding places were practiced in area R. The effects naturally appeared from immediately after the start and lasted for all the period under observation. No significant changes were seen in area C where no control measures were applied. Mosquito samples collected by the traps were identified and disected. Almost all specimens were Culex pipiens fatigans, and the always higher in numbers than the females. The ratios of young females (nulliparous and with the ovarial follicles of Stage I) were found to drop remarkably in areas where the larval control measures were practiced. The parous rates of females varied by the collections, and no significant changes were seen even in areas of residual sprays.

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In the summers of 1962 and 1963, field experiments on the repellents to chicken-biting Culicoides species, C. arakawae and C. odibilis which are dominant components of the biting midge populations, were carried out in three poultry farms isolated from each other at the Tama-kyuryo Hill area in Yokohama City. For determination of repellency of three repellent formulations, the flock of chickens of either farm A or B was sprayed with emulsions of the repellents and successive change of the daily biting rates of midges collected by light trap at the treated pens as compared with the rates at the control farm. The spraying schedule on the two farms was changed from treated to control, alternatively. In parallel with the examination of the biting rate, the infection rate of Leucocytozoon caulleryi in a definite flock and the growth rate of both groups were also investigated. Formulation 1, containing N, N'-diethyl mtoluamide 5%, 20% pyrethrins 2.5%, piperonyl butoxide 2%, N-octyl bicylohepten dicarboximide 2%, and di-n-propyl i-cincomeronate 2% as main constituents, was more effective than formulation 2 containing the former compound and butoxy polypropylene glycol. Sprayings of 10-fold diluted emulsion of formulation 1 at the rates of 3-8ml per chick and 25ml per chicken inhibited the biting rates of Culicoides at the level of 90 to 95%. The effective duration of formulation 1 was about 1 week after a single treatment but prolonged to 2 weeks after repeated ones at 3-day intervals. In spite of rather successful protection of chickens from the feeding of biting midges, the infectivity of L. caulleryi to the birds was not lowered in 1962 where high prevalences of both biting midges and disease were shown, but other evidences indicated some possibility for protection of severe infection. The infectivity apparently decreased as a result of sprayings in the experiment of 1963 where the prevalences were comparatively low. In addition, prophylactic effect was observed on a flock treated against fowl pox infection. No adverse effects were noticed in the growth and health of chicks after repeated trials of formulation 1 at 3-day intervals over a period of 1.5 months.

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[in Japanese]

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During the early summer in 1963 an enormous number of mosquitoes had become a tremendous nuisance among the inhabitants in an area of Omiya district, the vicinity of Tokyo. The only one main breeding place was found to be a stagnating irrigation creek running through by the area. The control of mosquito larvae was carried out in the end of May by spraying floating dust of 3 per cent of Baytex on the surface of the creek along about one kilometer of length. Then the complete change on the breeding place was achieved by spilling the water away into rice paddy fields which followed a few days after the insecticide spraying. Observations on the density and the age composition of the adult population were carried out before and after the larval control for the period of one and a half of months. Collection of mosquitos was done in a station located about a half kilometer from the creek using light traps, dry ice-mosquito net traps and inside resting collections in a chiken hut. The population density was observed to show a rapid decrease after the control and by the time of two weeks after the control it reached a minimum, that is, about 10% of the original level before control. Thereafter the population recovered gradually and regained its original size in the beginning of July. The age determinations were done according to the Detinova's method and the number of relics for individual mosquito were recorded. The parous rates individual mosquito were recored. The parous rates indicated 9.3% and 8.3% for the collection by dry ice method and by resting collections respectively before the control. Two weeks after the control they reached up to 91.7% and 57.4% then dropped again to 11.0% and 4.0% respectively in the beginning of July. It is obvious that the changes in the parous rate were reversely correlated with the transition in the density. A fact that a remarkable increase of parous rate was encounterred in two weeks after the control when the depression in the density occurred clearly suggests that the decrease of the population was caused exclusively by the eradication of the larval stage of the mosquito.

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[in Japanese]

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