After a strain of A. sinensis from Kanoya, Kyushu (Japan) was established by induced copulation with a human blood source for its first 26 generations, it has been further colonized for 19 generations in a small cage (30×30×30cm) by free mating at 25±1℃, 70-80% R. H. Larval stages were mass reared on the pulverized food consistng of equal weights of wheat germ, dry yeast and oatmeal. The mating ability of males during induced copulation was investigated; 3 day-old males were completely successful at mating but the quantity of sperm in the spermathecae was very low. The insemination rates were about 16% in the 31st generation, 41% in the 41st generation. A. lesteri has also been maintained mainly with a mouse blood source in a small cage for 15 generations without induced copulation. The insemination rate of this species was about 8% at the 11th generation. The tolerance of the eggs of A. sinensis to desiccation was tested and it was found that the eggs hatched normally after 2 days of desiccation but the hatchability decreased down to 29% after 4 days.

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The subcostal pale spot (Sc p) and fringe pale spot (F p) which are the distinguishing features between Anopheles sinensis and A. lesteri have been found to have a wide variability. The F p (+) of A. sinensis was lacking in 0.3% to 20.5% of individuals examined while the Sc p (+) was a comparatively more stable character, lacking in 0.8% to 6.4%. In A. lesteri, the F p (+) occurred in 1.6% and Sc p (+) 24.9% of the mosquitoes studied. The F p (-) is considered to be stable in A. lesteri. A new kind of wing spot (H p : humeral pale spot) that had never been reported in A. sinensis was found in the Tomakomai and Engaru strains; the rates of appearance of the spots were 23.3% and 23.7% respectively. The frequency of clasper movements in the males of the Tomakomai and Engaru strains during induced copulation was 14.3 and 14.6 respectively, whereas it was about 8 in the males of the other three strains of A. sinensis; this difference was significant at the 1% level. Moreover, these two strains showed a significant difference in the frequency against all the other 5 species or strains tested. From these results it is suggested that there have occurred genetic divergence in the Tomakomai and Engaru strains from the ancestral A. sinensis.

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Tabanus masamitsui, a new species is described from Okinawa Island. This species is quite similar to T. otsurui Ogawa, but differs from T. otsurui in the narrower width of frons, larger lanceolate middle callus, more slender palpus, and the slightly darkened color of wings.

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Hybomitra harai, a new species is described from the central and western parts of Honshu Island. This species is closely allied to H. jersey (Takahasi) and H. hirticeps (Loew), but H. harai can be distinguished from H. jersey by its broader frons and whitish markings on glossy abdomen, and also from H. hirticeps by its acorn-shaped basal callus and pollinosed subcallus.

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Parasitus gregarius n. sp. (Acarina : Mesostigmata) collected from livestock and poultry manure is described and illustrated in this paper.

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Comparative rodenticidal effectiveness of five anticoagulants were examined in single and multiple dose administrations. The acute toxicities obtained in this study were rather low in mice for both the coumarin derivatives and the indandiones, whereas those shown in rats were remarkably high. In the subacute testing, the indandiones were shown to be the more potent rodenticides of the chemicals tested. Also, coumatetralyl given to mice was least effective of the five chemicals tested, however, when given to rats, it showed nearly the same effectiveness as the indandiones did. The coumarin derivatives failed to attain 50% mortality at lower dosages in the subacute test, which may indicate a threshould concentration for these chemicals. When the rodenticides were given to rats and mice as the baits, high mortalities were obtained for all of these studied, but the differences among the chemicals were not observed in contrast to the results obtained in the oral administration tests.

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In order to analyze the endocrine system involved in control of oogenesis in the housefly, Musca domestica vicina Macquart, the function of corpus allatum was investigated with special reference to the action of juvenile hormone. After emergence of female fly, the size of corpus allatum increased and attained to the maximum size at the vitellogenic stage. When newly emerged flies were decapitated or starved, both corpus allatum enlargement and follicle growth were inhibited conspicuously. Follicle growth was also inhibited in allatectomized one. These results imply the function of corpus allatum involved in control of housefly oogenesis (Fig. 1). Allatectomized flies were topically applied with juvenile hormone analogue, methoprene (ALTOSID, ZR-515) and the effect on follicle growth was examined. Ovarian development of allatectomized one was stimulated distinctly with methoprene, and all the individuals treated showed ovarian maturation at the dose of 0.25μg (Table 1). Consequently it was proved out that juvenile hormone was a primary stimulus to regulate housefly oogenesis. As a next step of the experiment, influence of juvenile hormone on both processes of oogenesis-initiation and vitellogenesis was investigated. Growth of juvenile follicles in starved- and decapitated-flies was remarkably stimulated with methoprene (Fig. 2). Furthermore, methoprene stimulated markedly the vitellogenesis of normal-, allatectomized- and decapitated-flies which were fed on 10% sugar solution (Fig. 3). Thus juvenile hormone was shown to possess gonadotrophic as well as vitellogenic activity in the housefly.

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We have evaluated lethal effects of the insect growth regulator, PH 60-40 [N-(4-chlorophenyl)-N'-(2,6-difluorobenzoyl) urea], against the larvae of Culex pipiens pallens and Culex tritaeniorhynchus. A 25% wettable powder formulation of PH 60-40 was used for the tests. All test were conducted in 300ml glass vessels each containing 200ml of distilled and deionized water. A certain amount of PH 60-40 was added into each vessel to make suspensions with desired concentration of the active ingredient. Twenty 3rd or 4th instar larvae were introduced in each vessel and about 10mg of dry beer yeast were added as food every 2 days. The temperature of water in these glass vessels remined at 23°±1℃. Since mortality occurs during larval molts, in the pupal stage, and at the unsuccessful emergence of adults, all of these forms were checked every day until all survived larvae became adults to determine total or cumulative mortality. The calculated mortality, determined from the number of adult emergence, was corrected by Abbot's formula. The LC-50 dosage were obtained from eyefitted curves of the corrected percent mortality obtained at each dose. Larval emergence was not inhibited in the egg rafts of Culex pipiens pallens laid 12-18hr prior, but development of the newly hatched young larvae was. At the rate of 0.2 and 0.1 ppb PH 60-40 inhibited adult emergence almost completely. LC-50 dosages of PH 60-40 against larvae of Culex pipiens pallens were 0.035 ppb at the 3rd instar, 0.062 ppb at the 4th instar, and those against Culex tritaeniorhyncus were 0.042 ppb at 3rd instar, 0.060 ppb at the 4th instar, respectively. At the rate of 0.5 ppb, adult emergence from the 4th instar larvae of Culex pipiens pallens was completely inhibited, even larvae tested were introduced 7 days after the treated medium prepared. However, at the rate of 0.125 ppb concentration the lethal effects were decreased after 7 days definitely. In conclusion, PH 60-40 possess a significant lethal activity against the larvae of Culex pipiens pallens and Culex tritaeniorhynchus and appears to be a promissing candidate for mosquito controlling agent.

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Hatching of Aedes albopictus eggs were investigated to clarify their hatching stimuli and manner of their adaptation to environment. Eggs hatched at a higher rate in water containing Chlorella or at a low concentration of dissolved oxygen (DO) than in distilled water or water containing high DO. However, the eggs laid by adults, which had been exposed to shorter photoperiod (8 hours light) and/or delyed their blood-feeding, hatched at a lower rate in the same hatching media. Most of eggs kept wet for shorter than six hours after deposition, were killed with subsequent seven day egg-drying. Whereas eggs kept wet for longer than 24 hours, were not malformed but entered to quiescence by egg-drying. When those eggs were submerged in tap water or water containing a high DO, they hatched at a lower rate of no more than 20 percent, but the majority hatched after subsequent submergence in water containing Chlorella or a low DO. Thus, egg hatching response is determined by mainly concentration of DO, and by photoperiod and duration from emergence to blood-feeding at adult stage before egg-laying. Egg-drying after completion of embryonic development lowers the egg-hatching rates. We consider, the hatching response to DO concentration enables eggs to adjust their hatching to food quantity, and the lowered hatching response of eggs laid by delyed blood-feeding mosquitoes may imply their adaptation for avoiding increase of futile adult population when animal hosts are very few. The lowering effect of shorter photoperiod and egg-drying on egg-hatching response are considered their adaptation to overwinter at egg stage and that to prevent most of eggs from hatching just after a passing recovery of water level in their habitat according to a temporary rainfall, respectively.

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1. In order to investigate the feeding behaviour of the simuliid larvae, they were collected with polyvinyl-tape traps at a branch of Sagamigawa River, the northern part of Kanagawa prefecture, from August 1974 to May 1975 and the compositions of diatom flora in their digestive tracts were compared with those in the stream water, on the rock surface and on the polyvinyl-tape traps in the stream. 2. A great similarity of the diatom flora was found among the simuliid larvae of different species collected at the same location and time. 3. A great similarity was found between the samples collected from the rock surface and those from the stream water. 4. A great similarity of the diatom flora was also found among the digestive tracts, the rock surface and the stream water. Whereas, little similarity was found between the floras of the digestive tracts and polyvinyl-tape traps on which the simuliid larvae attached eventually. 5. It is concluded that the simuliid larvae feed on materials drifting (suspending) in the stream rather than those attaching on rocks.

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Culex pipiens fatigans rarely supports larval development to the infective stage of Brugia pahangi. But it might be noted that if the microfilaria can leave the blood mass and have migrated out of the stomach of mosquito it has a chance to be able to develop to the infective stage in the mosquito. Most microfilariae were trapped in the blood clot and destroyed within 36 hours after feeding on the infected cat. Different developments of filariae were found in the thorax of mosquitoes and only the same stage in each mosquito. Only few microfilariae reached the third stage and the susceptibility rate of C. p. fatigans to B. pahangi was 0.92 per cent.

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In this second paper, of the 18 species of black flies so far recognized in the Nansei Islands, the following 6 species belonging to 4 subgenera are treated : Simulium (Gomphostilbia) okinawense sp. nov., S. (G.) tokarense Takaoka, S. (G.) batoense Edwards, S. (Morops) yonakuniense Takaoka, S. (Odagmia) aokii (Takahasi) (new record) and S. (Gnus) bidentatum (Shiraki) (new record).

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Some ecological considerations were made on the distribution pattern of egg, larval (pupal) and imaginal populations of Aedes albopictus in a cemetery area of Nagoya City, central Japan in 1972. The mean crowding (m^^^*)-mean density (m) relation, or m^^^*=α+βm, was applied to the observed individual counts in order to analyze the distribution pattern of the mosquitoes of each stage. The results indicate that the basic components of the spatial distribution seem to be groups of several individuals, and that such small groups of each stage mosquito distribute aggregatively in the area. Two transformation formulae, y=log(x+1) and z=sin h^<-1>√<(β-1)/(α+1)x>, were compared in their efficiencies of stabilizing variance and normalizing variate frequency distribution, with a result that the former transformation was as useful as the latter.

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The changes of concentrations of Na and Cl in the haemolymph of fourth instar larvae of Culex pipiens pallens Coquillet, Culex pipiens molestus Forskal, Aedes albopictus Skuse and Aedes togoi Theobald, which were caused by treatment with artificial sea waters of various concentrations, were measured by radioactivation analysis. C. p. pallens showed no salt regulation (Fig. 1), but those reared in 20% sea water from first to fourth instar acquired a little ability of the salt regulation (Fig. 6). C. p. molestus was superior a little to C. p. pallens in salt regulation (Fig. 2), and A. albopictus was much more superior than the formers (Fig. 3). A. togoi reared in fresh water has an excellent ability of salt regulation (Fig. 4). In the highly concentrated 140% sea water, Na and Cl increased to the maximum values in about 10 hours. After 22 hours they decreased to ordinary concentrations (Fig. 5). This phenomenon shows that the additional strong function of salt regulation is prepared in 10 hours by their acclimation to the highly concentrated sea water. Water temperature renders much influence for the larvae to aquire this function. The concentrations of Na and Cl changed at different rates, and Cl always changed faster than Na.

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German cockroaches Blattella germanica Linne have been known to inhabit regularly definite types of properties such as office buildings, restaurants, hotels, shops and so on, but quite few also inhabit Japanese style wooden houses in Japan. In order to clarify the reason for this behavior, experiments and observations were made on the populations bred in several different environments. 1. Experiments of adaptability to three different structural materials In order to evaluate the adaptability of cockroaches to different structural materials which they inhabit, cockroaches were bred on the surfaces of wood, metal and plastic, at an insectarium kept at 25°±1℃. The periods of larval development were 51.9,56.1 and 59.9 days in male and 53.1,58.8 and 60.1 days in female, on wood, metal and plastic, respectively. It seems that wood is more favorable to German cockroaches than metal and plastic. 2. Comparison of developmental periods of larvae in seven different enviroments The larval periods of breeding groups bred in four different types of properties and under three different constant temperatures were compared during the periods from June to August, 1972. The larval periods were 52.4 days in a concrete office building, 63.6 days in a wooden apartment, 68.9 days in a concrete apartment, 70.0 days in a wooden house and 59.0 days under a constant 25℃, respectively. First instar larvae failed to develop into adults when kept constantly at 15℃ or at 10℃. 3. Comparison of life spans in three different environments Successive breedings were conducted in three different environments, in a concrete office building in Kawasaki, a wooden house in Yokohama and in the insectarium kept at 25°±1℃, and the pattern of life span under natural conditions throughout two years were observed. At the insectarium, six generations were passed successively during the two years without any change of characteristics. For instance, the average of developmental characteristics were as follows : embryonic period 21-28 days, larval period 59.0 days, the period prior to oviposition 9.8 days, frequency of oviposition 7 times in max. and 4.6 times in average, number of hatched larvae per ootheca of the first oviposition 36.8,and longevity of the male 90.0 days and the female 164.6 days. In summer, the cockroaches developed in a concrete building, as well as at the insectarium kept at 25℃. Of four successive generations observed for two years, two failed to survive the winter due to low temperature, because of lack of central heating. On the other hand, when there was central heating a generation was successful in overwintering and reproduced again beyond the winter. And in another one, some individuals overwintered successfully, but no reproduction occurred beyond then. Although they were able to breed normally in Japanese style wooden houses in summer, it seemed unlikely that they could establish themselves regularly there, because of severe low prevailing temperature as compared with concrete building centrally heated, in where room temperature was kept above ca. 15℃ even at midnight of winter. It was concluded, finally, that establishment of German cockroaches to definite types of properties depends principally upon the temperature conditions. Generally speaking, in Japan, they are able to inhabit concrete buildings regularly that there is central heating, on the other hand it seems to be very difficult to establish themselves in Japanese style wooden houses. But, if there are any continuously heated places such as refrigerator or boiler, it might be possible to do so.

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A new species belonging to the subgenus Dasyphoromima of genus Pyrellia R.-D., P. tateyamensis n. sp., is described and figured from Honshu, Japan. This species is closely related to P. pavlovskyi belonging to the same subgenus from USSR. This is the third species belonging to Dasyphoromima.

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