In the present paper, symptomatology and histopathology of a newly discovered cytoplasmic polyhedrosis of the smaller tea tortrix, Adoxophyes fasciata, were described. The diseased larva lost its appetite, which resulted in a marked reduction in the body size. The larva became sluggish and its color became whitish, especially in the ventral region of the abdomen.
Upon opening the larva, the midgut was characteristically white. Electron micrographs demonstrated that icosahedral virus particles about 55-60nm in diameter developed and occluded onto polyhedra in the virogenic stroma formed in the cytoplasm of midgut cells.
The polyhedra were generally icosahedral and had a size of about 1.2μ in diameter, but occasionally cuboidal polyhedra were found. The virogenic stroma contained complete virions, polyhedra, dense granules as core material, fibrillar material, most likely protein, and crystallogenic matrix which surrounded the developing polyhedra, but no cellular components.

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In the present study larvae of the rice stem borer, Chilo suppressalis WALKER which were either bred on a semi-artificial diet or collected in the paddy field, were used to rear a gregarious internal parasite, Apanteles chilonis MUNAKATA to compare the biological characteristics of the parasite. Rearing the parasite on larvae bred on the semi-artificial diet decreased the longevity of adult female, the number of mature eggs in ovaries, the number of eggs laid by a single female and the survival rate. Moreover, either females or males of the parasite were produced more frequently from the host larvae bred on the semi-artificial diet. It is not determined in the present study whether inbreeding of the parasite or the change of the host physiological condition resulted in these deleterious effects.

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To elucidate the characters of flight and the effect of physical factors on them, adults of the brown planthopper were tethered for flight by attaching a fine glass pin to the dorsum of the thorax coloured with a water-colour paint. The flight can be classified from the viewpoint of its duration to the following 3 types: (1) continuous flight for several hr, (2) repeated flight of short period and (3) no flight. Most individuals belonged to the 1st type, suggesting that this planthopper had the ability of long-range migration. Live-weight of body decreased greatly during several hours from the beginning of flight and then the rate of decrease diminished. Rearing temperature in teneral period affected its duration. The higher the temperature, the shorter was the duration of the teneral period. Its duration in the female was about a day at 27.5°C and several hours shorter in the male. Threshold temperature for flight was about 16.5°C in average. Above this threshold, there was little variation in the duration of flight. The stronger the wind velocity, the shorter was the flight duration. Flight was stopped at over about 5.5m/sec of wind. The higher the relative humidity, the longer was the flight duration. Particularly at 85% RH, many individuals flew for more than 10hr. Average flight duration under the conditions of 27.5°C, 60% RH and the wind velocity of 3m/sec, was about 4hr, although individual variation was great. It is probable that such variations resulted from internal factors such as the quantity of energy source for flight, rather than from external structural differences. These results suggest that this species can migrate long distance during the rainy season in Japan, Tsuyu, when the temeprature is relatively low and the humidity is high.

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The thermal relations of development of the diamond-back moth, Plutella xylostella, were compared for three different local stocks in Japan (Sapporo, Hiratsuka and Kagoshima) and one from Djawa (Batu, Malang). The threshold temperature and thermal constants for development of one generation were calculated from the regression of the velocity of development from the egg to adult emergence on temperature. The Hiratsuka stock had the highest threshold temperature of 9.5°C, and this was followed by the Malang stock with the threshold of 8.6°C, while the Sapporo and Kagoshima stocks showed comparatively lower values, 7.5°C and 7.4°C, respectively. Variation in the thermal constants showed the reversed tendency; the Sapporo stock had the maximum value of 313 degree-days, the Kagoshima (294 degree-days) and the Malang (250 degree-days) stocks followed this, and the Hiratsuka stock took the minimum of 229 degree-days. There was a negative correlation between the threshold temperature and thermal constant. The local difference in the regression of the velocity of development on temperature was tested by means of covariance analysis, which revealed that the regression coefficient (b) was significantly different between the Hiratsuka and the Sapporo stocks, and between the Hiratsuka and the Kagoshima stocks. Furthermore, there was a significant difference in the regression intersect (a) between the Sapporo and the Malang stocks; however, no significant differences existed among any other combinations of the stocks. These results seem to imply that there is a slight local differentiation in the developmental characteristics. The differentiation, however, is not related to the geographical location, nor to the climatic gradient.

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This investigation was carried out in forests situated at altitudes ranging from 500 to 520m on the eastern side of Mt. Shirataka (in Yamagata Prefecture). The forests were composed of young broad deciduous trees, young Japanese red pine (Pinus densiflora SIEB. et ZUCC.), or young Japanese ceder (Cryptomeria japonica D. DON.). Wood mice were captured by means of mouse live traps with sweet potato and corn as baits. The investigation was carried out during the period from June 1969 to May 1971. The tendency of Microtus montebelli fixing its habitat was very strong: the percentage of the migration number covered only 11.1% of the total animals. The migration occurred from April to August, being most active from February to October. The migration percentage of Clethrionomys andersoni was 22.2% of the total, and the migration area was very small. The migration time was from February to November. Apodemus speciosus showed very strong migratory habits and the percentage of the migration number was 36.7% of the total. The migrating area was wide. This species seems to migrate from one location to another according to the abundance of foods and the migration time extended from April to November (nonsnow season). The migration percentage of Apodemus geisha was 20.5% of the total number, and the area covered was very wide. The migration of this species was seen all the year round but the migrating one was only the male. The periods of the catch of each species in the year were as follows; 11 months for Apodemus geisha, 10 months for Apodemus speciosus, 8 months for Microtus montebelli, and 4 months for Clithrionomys andersoni.

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Eggs of the winter cherry bug, Acanthocoris sordidus THUNBERG are laid in masses, and the larvae live in tight clusters during their early instar period. The tendency for aggregation decreases as the larvae grow. In order to analyze the aggregation pattern of this species, the distribution of individuals on the host plants, winter cherry, was examined for an experimental population in the green house and for a field population at Kurama district in Kyoto. The data obtained from the experiment were analyzed by using the relative measure of aggregation, *m/m and the τ index. It was revealed there were three dispersal periods in the course of development from egg to adult, which resulted in important changes in the distribution. The first dispersal period which mainly took place at the second instar stage tended to increase local concentration of individuals, but the second one which occurred mainly at the fifth instar stage inversely made the distribution less contagious, and the last one at the adult stage did not in anyway affect the basic pattern of distribution. Moreover, the spatial distribution patterns in successive stages of development were examined by using the *m/m regression method for both the experimental and natural populations. It was found that the two cases showed similar tendencies. The value of α decreased as the developmental stage proceeded, which indicates the gradual reduction of basic aggregation units. The value of β was larger than unity in all stages, which indicates the contagious distribution of basic aggregation units. The β value increased until the second and third instar stages, and thereafter decreased, which was in accord with the dispersal processes mentioned above. As a reason of the clumped distribution of larvae, the mutual attraction among individuals was supposed to be more important than the heterogeneous conditions in the environment.

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