The present study concerning variations in salivary amylase and protease activities of Lygus disponsi LINNAVUORI has shown that the enzyme activities varied with the season, the individual and the developmental stages. The amylase activity had a tendency to diminish at low temperatures (2°C) and after prolonged periods of starvation (24 hr). The variation in the enzyme activities between a pair of the salivary glands in a bug was small for amylase but large for protease. The correlation between amylase and protease activities was insignificant. Some causes of individual seasonal variations in enzyme activity, and differences between production systems for amylase and protease are discussed.

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Seasonal variation of the physical and chemical characters of soils was studied in four habitats under different vegetations where oribatid faunas were investigated. The variation of soil characters was seasonally observed and the values of the chemical properties which increased from middle winter to summer were recorded. On the other hand, soil textures were almost all classified to light clay and clay. Extreme variation in physical properties could not be found among profiles.

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For the purpose of investigating the relation between the faunistic composition of oribatid mites and the vegetation of their microhabitats, sampling tests were carried out in Nopporo National Forest near Sapporo during ten meteorologically selected seasons in the year 1967. The samples were taken from the microhabitats on and under four different kinds of vegetation, i.e. natural broad leaf forest land (plot Bf), second-growth coniferous forest land (plot Cf), cut-over area with sasa-bamboo (plot Sb) and grassland (plot Gl). The sampling was made by means of a rectangular metal sampler measuring 5×4×5 cm, or of picking up with small forceps. The samples were spread on the bottom sieve of modified TULLGREN apparatus in order to extract oribatid mites.In total, 299.6 (per 1000 cm³ of bark, and 200 cm² and 19 cm in depth of organic and mineral soil layers) adult oribatids of 47 species from plot Bf, 236.3 (per 1000 cm³ of bark, and 200 cm² and 17.5 cm in depth of organic and mineral soil layers) adult oribatids of 35 species from plot Cf, 75.1 (per 200 cm² and 16 cm in depth) adult oribatids of 26 species from plot Sb, 68 (per 200 cm² and 15 cm in depth) adult oribatids of 4 species from plot Gl and, in sum total, 679 adult oribatid mites of 53 species were collected. The humus horizon of plot Bf had the largest number of species of oribatid mites among all the strate of the four plots. In the grounds under the fo urkinds of vegetation surveyed, the population density of oribatid mites reached a peak during the period from late autumn (LA) to middle winter (MW).

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A new method was introduced for the quantitative evaluation of the effectiveness of rat repellent. With this new method experiments on cycloheximide was carried out. The repellency of cycloheximide was found to be due to its disagreeable taste. Using the electrophysiological method, the taste response to cycloheximide was recorded from the glossopharyngeal nerve.

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Parasitic activity of wasps attacking delphacid eggs on cultivated plots and the intensity of their dispersal were studied by setting in the outdoors flower-pots bearing Laodelphax striatellus eggs. Anagrus nr. flaveolus was an overwhelmingly dominant species. The parasitic activity of the species was ascertained on wheat late in April. It was also clarified that the parasite had already existed on the early-season transplanted rice crops when the adults of L. striatellus were about to invade. An increase of parasitic activity in autumn was demonstrated on paddy plots. Dispersal of Anagrus to a bare ground on which the research was carried out tended to be continuous all through the season. In autumn, the intensity of dispersal was heightened remarkably. Adaptive significance of the autumn dispersal is discussed in relation to possible ways of hibernation of the parasite. A different species of Anagrus and a trichogrammatid belonging to genus Oligosita were also recorded occasionally in autumn. The species, however, were mainly obtained on the bare ground and are guessed to be mere facultative inhabitants on rice crops.

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The relations between gall formation and phosphoric metabolism were studied by cross-grafted tomato plants with different susceptibilities. Cross-grafted plants of susceptible tomato (line "Black") and resistant ones (line "Anaf" No. 2 or No. 3) were inoculated with 5, 000 larvae of Meloidogyne incognita per plant. Fifteen days later, 25 μCi of ³²P-orthophosphate was given to the resistant line so as to be absorbed from roots with full nutrients. The data showing the following gall indices, 100 in intact susceptible plants, 0 in intact resistant plants, 85 in resistant scion on susceptible stock, 17.5 in susceptible scion on resistant stock, indicate that the resistant or susceptible factors may be associated with both roots and tops of plants. Autoradiography and wet combustion analysis of plant tissues showed marked accumulation of ³²P-phosphates on the galled roots. Barium insoluble phosphate-esters, which mainly include nucleotides, were more at gall tissues than at healthy roots.

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The adenosine triphosphatase (ATPase) activity in the posterior silk gland cells of 72-hr-old, fifth instar larvae of Bombyx mori L. was studied histochemically. Fine reaction products of ATPase were found only along the microvilli of the apical region. Dense reaction products were detected within the intracellular spaces in the apical region. Within the nucleus, fine raction products were also detected in the nucleoli and chromatin. The distribution of ATPase suggests that it may be involved with the secretion of silk protein into the lumen from the cytoplasm or with reabsorption of water into the cytoplasm from the lumen.

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