Comparative studies were made on the pleural structures of the thorax of adult mosquitoes of 58 species collected from Japan. It was demonstrated through these observations, that tribes, genera, subgenera, some species-groups or species could readily be separated by the pleural characters, such as the presence or the absence, or the numbers and the arrangements of certain bristles and/or scales. The figures of each species and the key to differenciate these groups by the pleural structures were presented together with the description in Japan for all the species concerned. The above study suggests that examination of the pleural structures of the mosquitoes are of essential taxonomic importance, and that it often provides information most convenient or valuable for the identification of the species or species-groups of the mosquitoes.

View full abstract

So few reports on the avian flea fauna from Japan, that the author describes of some notes on each species in this paper. During the year of 1962 and 1963, twenty-four nests of the Japanese house-martin, Delichon urbica dasypus, were obtained from various parts in Hokkaido. 12017 fleas representing four species were obtained from these nests. The species are Ceratophyllus farreni chaoi, Callopsylla (Orneacus) waterstoni, Ceratophyllus olsufjevi, and Frontopsylla (Orfrontia) sp. The detail of the results of the census of fleas in nests from eight districts are shown in Table 1.

View full abstract

Investigations on the mosquito larvae over-wintering in the bamboo groves in Utsunomiya and Oyama were carried out from January to March, 1962 and from November, 1962 to February, 1963. 1) In the stumps of Madake, Phyllostachys reticulata, mosquito larvae could not be collected at all throughout the winter. 2) In the stumps of Mosochiku, Phy. edulis, 1, 454 individuals belonging to four species were obtained : Tripteroides bambusa (45.9%), Uranotaenia bimaculata (38.4%), Armigeres subalbatus (15.1%), and Aedes flavopictus (0.7%). 3) Three species of mosquitoes, Tr. bambusa, Ur. bimaculata, and Ar. subalbatus, overwintered as larvae in the Mosochiku stumps protected against cold and dryness.

View full abstract

A patient (43 years old, ♂) who expectorated larvae and pupae of Psychoda alternata Say (Diptera : Psychodidae) in sputum was reported in this paper. During the last four years the patient has suffered from bronchiectasis, and for the last two years his breath has had an offensive odor. With his offensive and fetid odor, the gathering of moth-flies and other undetermined small flies around his face has been observed by the patient. This phenomenon was conspicuous when he lay down. The cause of this phenomenon is presumed as the existance of certain chemical in his breath that attracts these flies. In his discharge, flies were observed four times, during the period from the end of May to the middle of June. The stages of discharged flies were of larval at the first and the second time, and were of pupal at the third and fourth. Vigorous movement of the larvae were observed immediately after their discharge. The route of infestation was presumed as follow. The laying of eggs by the adult female attracted by the odour of patient's breath, was done on the moist part arround his nose or mouth. And then the movement of the eggs or hatched larvae into his trachea happened when he inspired and the growth of larvae was done internally.

View full abstract

In order to know the contact toxicity of several insecticides against an unusual poisonous beetle, Paederus fuscipes Curtis, a seris of tests was carried out under laboratry conditions. Overwintered adult insects collected from Koga, Ibaraki Prefecture, were used. Five emulsion of insecticides, γ-BHC (lindane), DDT, chlordane, diazinon and DDVP were tested through residue contact method using impregnated filter papers in various concentrations, and LC_<-50> values were assessed from the obtained results. It was confirmed that lindane is most excellent in the LC_<-50> value, and DDT comes next; but its concentration-mortality regression line shows a gentleslope; the others are following sequence of descending oder in the LC_<-50> value : i. e. diazinon, chlordane, DDVP.

View full abstract

Following 1961 and 1962 experiments, a series of spray tests, in order to check the residual effect of Sumithion and Dipterex, were carried out using several summer-huts located in Hachioji-city, west of Tokyo. 1. During May-June period of 1963, residues of 0.5% Sumithion emulsion (0.25 gram of active ingredient per squaer metre) gave 80-99% knock-down for about one month against susceptible Takatsuki flies. Difference in the knoc kdown effect between the shadowy huts and the sunny huts has hardly been recognized 2. Residues of 0.5% Dipterex emulsion (0.25 gram Dipterex per square metre) showed about 70-80% knockdown effect against susceptible (Takatsuki) strain through 35 days in the shadowy huts located among the trees. Against diazinon-resistant flies (RP strain) the residues of Sumithion and Dipterex gave a higher kill than that of diazinon, but a slight cross-resistance with diazinon would not be denied.

View full abstract

Field control tests against diazinon resistant houseflies were carried out during July 15 to October 15, 1963, in Mihara areas of Hokota Village, Ibaraki Prefecture. DDVP emulsion was treated as residual spray or larvicides in 5 areas, while DDVP bait, named "fly cake", was applied in 4 areas. By residual spray or larvicidal treatment, at 0.15 gram to 0.25 gram in active ingredients per square metre, the fly population estimated by ribbon traps decreased considerably, but more satisfactory effect was obtained by using 0.25% DDVP bait.

View full abstract

1) The control tests of mosquitoes and flies by residual spray of dieldrin and Baytex were conducted in Amami Island, an endemic area of Bancroftian filariasis, in summer of 1962. The resistance levels of mosquitoes and flies, i. e. larvae and adults of Culex pipiens and Armigeres subalbatus, and adults of Musca domestica vicina and Chrysomya spp., after three applications of the chemicals were compared with the susceptibility levels assessed before the applications. 2) The residual spray of Baytex was highly effective to housefly and mosquito, though not so effective to Chrysomya spp. The applications of dieldrin were scarcely effective both to housefly and mosquito. 3) Among four species of mosquitoes and flies, Armigeres subalbatus showed of high resistance by the residual spray of dieldrin, and the adults of C. pipiens showed of slight resistance to dieldrin. All of four species have not showen any marked resistance to Baytex, and those except the above two species also have not shown of any marked resistance to dieldrin.

View full abstract

Denken and Kunetsu colonies of Culex pipiens and Denken and Yui colonies of the same species were selected by the treatments of dieldrin and Baytex, respectively, both in adult and larval stages for several generations in laboratory, adopting the dipping method in larvae and the topical application method in adults. After the results, any marked resistance has developed neither by the selection of dieldrin nor by that of Baytex. Though slight increase of LD_<-50> in adult mosquitoes were observed. This may perhaps be ascribed to the fact that those colonies were already highly resistant to dieldrin. To Baytex, in the contrary, the colonies were susceptible and the resistant gene to Baytex was not or scarcely existent in the populations.

View full abstract

It is rather curious that any attempt has not been made to control the larvae of Culex tritaeniorhynchus in the paddy field despite of the fact this is the most important vector of Japanese B encephalitis in this country. Along with helicopter spray of various insecticides against the rice-stem borer at the Mizukaido area, Ibaraki Prefecture, a spray test of 2% Baytex dust was made on July 16th, 1963, against the paddy-field mosquito larvae in the same area. This test was followed by a series of model experiments using various Baytex formulation in the field and laboratory. 1. By aerial spray of 2% Baytex dust, 30kg per hectare (60mg/m^2 in active ingredient) the larvae of Culex tritaeniorhynchus and of Anopheles hyrcanus sinensis in the paddy field were checked for three days. On the fourth day, however, in some spot of the treated area a few earlier instar larvae were found to develope, and on the sixth day grown larvae were recognized also. The whole population of the mosquito larvae almost recovered on the tenth day. 2. A small-scale application at a paddy field at Toyoda, west of Tokyo, revealed that 2% Baytex dust fails to kill the larvae on the seventh day of the application. On the other hand, 5% grains of Baytex strewn on the paddy field (60mg per square metre in active ingredient) showed 14 days efficacy when tested by the water of the paddy field. 3. In order to compare the residual effects of five Baytex products small artificial rice-fields, one square metre and framed by concrete, were used. The active Baytex ingredient was equally 60mg per square metre, this is about 1 ppm to the water within the frame. The effect of each products is as follows : 1% floating dust 6 days, 5% grain 8 days, 2% dust 5 days, emulsion 2 days, wettable powder 1 day. 4. Small pots in which rice-plant was deposited, were used for further comparison of the residual effect of the five products. Each product, one ppm in active ingredient, were added into the water, and Culex tritaeniorhynchus larvae reared in laboratory were put into it at ceatain intervals. 5% grain lasted at least 14 days, one percent floating dust was effective until 7th day, 2% dust and wettable powder gave similar result with the floating dust. 5. It may be concluded from the model experiments that Baytex floating dust or grains must be more promising than the 2% dust applied at the practical text.

View full abstract

Field control tests by insecticides against Anopheles sinensis and Culex tritaeniorhynchus were carried out from June through August, 1963, in a paddy field, Kawasaki. Wettable powder and granules of DDT, wettable powder, granules and floating dust of Baytex and Dieldrin dust were tested with various dosages. Little difference was recognized between DDT and Baytex, though the former seemed to have slightly longer residual effect than the latter. Application of wettable powder and floating dust gave better effect than that of granules. Regarding DDT and Baytex wettable powder as well as Baytex floating dust, 0.1-0.5ppm or 10-50 mg/m^2 in active ingredients should be applied to obtain a practically effective result. When a longer residual effect is expected, at least the dosage of 1.0-3.0 ppm or more of DDT wettable powder or Baytex floating dust should be applied.

View full abstract