Some considerations were made about the minimal number of samples for obtaining population fluctuation curves of mosquitoes on the basis of light trap collections in a given area and in a week. (1) In dealing with these subjects, the mosquito counts were transformed into y=log(x+1) values to normalize the data, and seasonal fluctuation curves were expressed by the Williams' means (Mω=antilog y^^^--1) obtained from the data thus transformed. Two kinds of the fluctuation curves were obtained from the periodical sampling data : one kind of the curves was derived from each of the mean values Xi (i=1,2,…, 15,16) of log-transformed mosquito counts in the randomly and successively accumulated samples, and the other from the mean values Y (=X_<17>) calculated using the total sample. The similarity between the two kinds of fluctuation curves was compared by γ^2 values (coefficients of determination) between the two means, Xi and Y. The degree of agreement between Xi and Y was expressed by a and b values of the regression line, Y=a+bXi; and the precision of Y estimation by Xi was evaluated in terms of the ratio, σY・X_i/Y^^^- (%) (σY・X_i=standard error in Y estimation by Xi) (Figs. 1,2). As a result, about 8 sampling sites among the total of 17 were sufficient to obtain about 90% closeness of the two kinds of the fluctuation curves expressed by the Williams' means (Fig. 2). (2) The same procedure was applied to obtain the minimal number of samples in a week in a given sampling site. As a result, the light trap collections in three nights a week gave 90% closeness to the every-day sampling in the seasonal fluctuation pattern, when the trap was operated at about the same intervals (Figs. 3,4) (3) Discussions were given of the differences between the results in this paper and those reported so far with respect to the operation schedules of light trap in a week, from the view points of variability and convergency of each accumulated samples to the total ones.

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Two species belonging to the genus Azelia R. -D., namely A. cilipes (Haliday) and A. monodactyla Loew, were newly recorded from Japan. It was confirmed that the larvae of these species occurred from cow dung.

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The nectar-feeding activities of Aedes and Culex mosquitoes were investigated in the laboratory and field in 1974-75. The anthrone reaction by Van Handel (1972) was used to detect fructose in the mosquitoes. The feeding tests of three species of mosquitoes on the flowers of 11 nectar plants showed that Aedes albopictus was heavier feeder than other two species, Aedes togoi and Culex pipiens molestus, and the last was lowest in the feeding rate. The rate of nectar feeding, however, varied depending on the flower species offered. C. p. molestus appeared to feed heavily on some nectar flowers such as snowbell and sumac. The nectar-feeding activities of the mosquitoes increased gradually with the days after emergence; A. togoi fed on the flowers of chestnut tree reached a peak of 97.9% on the 9th feeding day. Both male and female A. albopictus which had been fed on the flower nectaries showed 80-90% feeding rate during 8hr after the feeding, but only 31% after 24hr, while the percentages of individuals reacted heavily with the fructose reagent decreased rapidly with the time elapsed. An investigation on natural nectar feeding of the wild-caught A. albopictus indicated that the feeding rate of males was significantly higher than that of females, 65.1% vs 53.6%, during the period from late-September to mid-October. The females of C. p. pallens, C. orientalis and C. hayashii collected from the caves during the winter months, from November to February, were anthrone-positive at the rates of 10.9%, 3.2% and 3.7% respectively. A small number of other species such as C. tritaeniorhynchus and C. bitaeniorhynchus were negative. When 13 females of the overwintering C. p. pallens fed on the loquat flowers in a laboratory cage in mid-December, 46.2% were fed heavily in 24hr. This proves some of the mosquitoes to re-feed on plant nectar during the early overwintering period.

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A survey on the thelazian parasites and their intermediate hosts was made in the farm of Miyazaki Livestock Breeding Station in Kobayashi City, Miyazaki Prefecture in July and October of 1973. Of five genera and 8 species, totaling 3,392 flies were collected from cow bodies and Musca hervei was dominant. M. hervei occupied 73.6% of total flies in July and 54.2% in October. Four flies of M. hervei (0.2%) in July and 6 flies of M. hervei (1.2%) in October were infected with thelazian parasites and no parasite was found from the other fly species. The infected rate of flies in Kobayashi City was much lower than that in Kanto district, especially than that in Chiba City which showed 18% in October of 1973. Totaling 83 thelazian parasites belonging to Thelazia rhodesi and T. skrjabini were obtained from cows, and T. rhodesi was dominant (93%). A survey in Okinawa Prefecture was made in Ishigaki City and Kunigami-Son, Okinawa main island in 1974. No parasites and infected flies were found in this area. It is supposed that no intermediate hosts are distributed in this district.

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Argas japonicus Yamaguti, Clifford and Tipton wintering in 2 Delichon urbica nests were collected at Agematsu, Nagano Prefecture, Japan, on November 17,1967. All the nymphs other than protonymphs were reared individually on chickens up to adults in the laboratory. Using the informations on the sex, retrospectively, following data were obtained. 1. The wintering population comprized 48 larvae (8.9%), 146 protonymphs (27.0%), 215 deutonymphs (39.7%), 10 tritonymphs (1.8%) and 122 adults (22.6%). 2. The sex ratios for the deuto- and tritonymphs and for the adult did not deviate significantly from half-and-half. 3. There was a very high regression of the idiosomal width toward the indiosomal length in the nymphal and adult stages. 4. The idiosomal lengths of the protonymph, deutonymph and adult were normally distributed, respectively. 5. Smaller sized deutonymphs oftener gave rise to tritonymphs in the laboratory. The difference by potential sex in the ratio of deutonymphs that passed through the 3rd instar nymphs was nonsignificant. 6. The idiosomal length of newly emerged ticks that were fed on chickens in the laboratory was described by the regression of the length of the preceeding stages. The regression coefficient was significantly larger in the female than in the male.

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The acaroid mite, Tyrophagus putrescentiae, is a household insect and commonly seen in Japan. This mite can be controlled using paper sheets which were sewed up to the entire upper and lower surfaces in Tatami-mat impregnated with fenthion. We conducted the safty evaluation on the paper sheets. Animals were maintained on the Tatami-mat or on the paper sheets during period of one, two and three months. The amounts of fenthion applied were 0 (untreated), 0.25,0.7,2.0 and 6.0g per m^2. In the practical amounts of 0.7g per m^2,the result indicated that there was no adverse effect on the general condition and appearance in the mice and rats as compared with untreated group. On the indirect contact test to the Tatami-mat, the inhibition of plasma and erythrocytes cholinesterase activities were observed in the mice after two to three months period. On the other hand, when animals were directly contacted on the paper sheets, the cholinesterase activity of plasma and body weight gain were reduced in the mice, and also, the inhibition of cholinesterase activity was observed in the brain of rats after one month period.

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The experiments to determine the safety of the paper sheets which were sewed up in the Tatami-mat impregnated with fenthion were made for male mice and rats. The amount of this compound was 0.7g per m^2 of sheet. These animals were maintained during the period of twelve-month. No adverse effect was shown on general condition, appearance and body weight gains. The cholinesterase activity of each animals were determind after three, six, and twelve months. No significant difference was indicated on the inhibition of plasma, erythrocytes, brain cholinesterase activity.

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The spider, Chiracanthium japonicum, has been well recognized as poisonous by common people in Japan. Especially in Tohoku, North Japan, this species has been most feared of toxic spiders and named "Kuchiguro" because of having black jaws for killing or paralyzing their prey. Eleven cases of arachnidism caused by this species were recorded during the periods from 1973 to July 1975. In the present paper, an analysis was made on total nineteen cases of arachnidism including the eight cases which had already been reported since 1956 in Japan. Results were as follows : 1. Arachnidism caused by Chiracanthium japonicum occurred from May to August with a marked peak in June. 2. Arachnidism in males was more frequent than in females and most frequent bites occurred in teenagers. 3. It was remarkable that many cases of arachnidism occurred during sleep at night by male spiders which were infesting houses. 4. The site of bites was most frequently observed in upper extremities. 5. The symptoms of arachnidism were characterized by local skin legion as continuous sharp pain, erythema, swelling, petechiae and pigmentation, and frequently combined with generalized signs of nausea, vomiting, loss of appettite, headache and shock. 6. In treating the arachnidism, it was a serious problem to relieve continuous sharp pain of biting area. The use of central analgesic such as narcotic drugs seemed to be effective.

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Under an assumption that the age of the population of female mosquito, Culex tritaeniorhynchus summorosus Dyar, captured in the pig baited traps will be older than that in the dry ice baited traps, the dimensional difference of the Ib follicular stage was compared between two populations. The follicular size of nulliparous and monoparous sac-like females, in the dilatation stages of a population in a pig baited trap was significantly larger than that of a population in a dry ice baited trap. However, the Ib follicular stage in each physiological age of the population in the pig baited trap was not significantly different in size between the specimens collected in the earlier and the latter half of the night, and such tendency was also recognized in the case of the population in the dry ice baited trap.

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The efficacy of the two JHAs, methoprene and hydroprene, to inhibit embryonic development of the human body louse, Pediculus humanus corporis and the bed bug, Cimex lectularius was evaluated. The LD 50's values of hydroprene against the body lice was 4.25μg per (cm)^2. Methoprene appears to be less effective than hydroprene. Contrary, methoprene was remarkably effective on the bed bug embryos, its LD 50's being about 7.25μg per (cm)^2,but hydroprene was not. Distinct differences in ovicidal activity between the 2 species were observed for these compounds.

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Field surveys of the distribution of domiciliary cockroaches were conducted in Tokyo and Kawasaki during the period between 1972 to 1974. In Tokyo, dead cockroaches collected from various types of buildings following insecticide treatment by pest control operators were brought to the laboratory and identified. Among a total of 286 buildings surveyed, 172 (60.1%) were restaurants and snacks, 25 (8.7%) offices, 14 (5.0%) food factories, 12 (4.2%) residences and 12 (4.2%) supermarkets. A total of 2,802 cockroaches was collected including Blattella germanica (93.7%), Periplaneta fuliginosa (4.8%), P. japonica (0.5%), P. americana (0.8%) and P. australasiae (0.2%). However, the findings cannot be taken to represent the general tendency of cockroach infestation in Tokyo since a disproportionately high number of restaurants and offices, which are the principal clients of pest control services, were surveyed. A correlation between the type of structural property and established cockroach species was examined and a dominance of B. germanica was shown in all cases. This was especially striking in the case of structures constructed within the past 5 years. In Kawasaki, a total of 145 cockroach adhesive traps were set in offices, restaurants, stores, apartments, residences and farm houses on two occasions in both summer and winter. Species compositon of trapped 1,755 individuals was B. germanica (78.6%), P. fuliginosa (20.7%) and P. japonica (0.7%). B. germanica was dominant over P. fuliginosa in offices, apartments, restaurants and stores, while the opposite was true for residences. In farm houses, P. fuliginosa was most abundant followed by P. japonica. A distinct tendency for the abundance of B. germanica in urban buildings, P. fuliginosa in residences and P. japonica in farm houses was observed. Furthemore, P. japonica has never been trapped during winter, suggesting that they had entered diapause.

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Some investigations on the chemical control of the larvae of chironomid midges were carried out in the Suimon river which runs through the center of Ohgaki City, Gifu Prefecture. The river was so heavily polluted due to drainage from the factories that no midge larvae could bread there before the Water Pollution Control Law was enforced in 1971. The midge-swarm problems arose in Autum 1973,because of the enforcement of regulation of the drainage from the factories which improved the biological oxygen demand in the water from 85ppm in 1970 to 12ppm in 1974. The density of the larvae per 40(cm)^3 (20(cm)^2×2cm in depth) of the bottom mud was estimated from 126 to 186 before the river was treated with temephos. In the laboratory test, 45% of the tested larvae was killed and the survivals were intoxicated at 12 hours after the treatment when they were dipped into 0.8ppm (AI) of temephos WP for 60 minutes. In the field test, the river was treated with the temephos WP for 60 minutes at 1ppm of the flowing water volume. At 9 days after the treatment, no midge larvae were found at about 1.6km downstream from the application spot. The temephos showed no poisonous effects on a loach up to 10ppm in the laboratory test. A loach, carp, crucion and top minnow habitating in the river were not affected by the temephos treatment.

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A study was carried out on the spider fauna of houses in different environments of Nansei Islands, South Japan. In total 24 species belonging to 17 genera and 11 families were collected, among which 11 species were common spiders in houses. No dangerous spider was found in any houses in this survey.

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The spider, Heteropoda venatoria, has been known to be an effective natural enemy of pest insects like cockroaches and flies. The field study on the geographical distribution of this spider was made during the periods from 1963 to 1966 and from 1972 to 1973. It covered 174 points in 42 prefectures. Results were as follows : 1. This spider was recorded at 137 points in 35 prefectures. 2. This spider was found more abundant in the southern parts of Japan, as Kyushu and Chugoku districts and in the Pacific side of Honshu Islands including many southern remote islands. 3. The northern boundary of habitats of this spider was found to lie on the area of six different prefectures, namely Ibaraki, Tochigi, Gumma, Nagano, Toyama and Ishikawa Prefecture. Those prefectures lie at 36°-38°North Latitude and in the zone of the annual mean temperature of 12°-14℃.

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The development of resistance of houseflies to organophosphorus compounds at the dumping-islands in the Tokyo Bay has been reported by the present author since 1966. In the 3rd "Yumenoshima" where full coverage of OP spray is being performed daily, an enormous number of single fly species, Musca domestica vicina, has been established. The LD 50 values of flies collected from the 3rd "Yumenoshima" in June, 1974 were correlated to those of the 15th dumping-island colony in 1973. In September, 1974,a remarkably increased OP resistance was found, with the LD 50 values of 5.21 microgram for diazinon, 54.9 microgam for fenitrothion, 9.62 microgram for fenthion and 0.581 microgram for dichlorvos. On the other hand, they were still susceptible to pyrethroids.

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[in Japanese]

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