Acta Arachnologica
Online ISSN : 1880-7852
Print ISSN : 0001-5202
ISSN-L : 0001-5202
Volume 25, Issue 1
Displaying 1-5 of 5 articles from this issue
  • Hisatoshi KOBAYASHI
    1973 Volume 25 Issue 1 Pages 1-9
    Published: 1973
    Released on J-STAGE: March 29, 2007
    JOURNAL FREE ACCESS
    The present paper deals with the descriptions of two new species of the genus Sarutana, S. silvicola and S. abensis. These species have following generic characters.
    1. The outer margins of the maxillae, in the male, are strongly concave and the same shape is found in Masirana. In Falcileptoneta and Europian species, the maxillae are normal.
    2. The chelicera bears 8 teeth on the promargin of fang furrow, as in S. glabla and S. kawasawai, There are 8-11 in Falcileptoneta and 10-11 in Masirana.
    3. In the male palp, the femur with three rows of many spines on dorsal, ventral and prolateral.
    4. The apical end of the retrodorsal side of palpal tibia bears a special apophysis. The apophysis, in Sarutana, divergent and the shape is the characteristic of species.
    5. The emboli of S. silvicola and S. abensis have many teeth, as in S. kawasawai, while Falcileptoneta and Masirana have a sickle-like emboulus.
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  • Studies on the life-cycle of spiders, Oedothorax insecticeps Bös. et Str. and Enoplognatha japonica Bös. et Str.
    Hozumi TANAKA
    1973 Volume 25 Issue 1 Pages 10-15
    Published: 1973
    Released on J-STAGE: March 29, 2007
    JOURNAL FREE ACCESS
    In order to bring to light the life-cycle of two species of spiders, Oedothorax insecticeps Bös. et Str. and Enoplognatha japonica Bös. et Str., the investigation was carried out under field and laboratory conditions at Sakai City from 1969 to 1970.
    The results of the observations were as follows. O. insecticeps has two generations a year. The adult appears from October to May and again from June to September. This spider passes the winter in the adult stage in the stubbles of rice plants. The eggs of the first generation are laid in the stubbles of rice plants during the period from March to June. During the standing of rice plants in paddy field, this spider inhabits around the rice stubbles. A female of the lst generation makes about 4 egg-sacs and 42 eggs are deposited in one sac. These egg-sacs are placed on stems of rice plants from late August to early October. The eggs hatch in 7-8 days in paddy field, and development from egg to adult takes 60 days in female, 55 days in male. This spider moults four times.
    E. japonica hibernates in various insters of nymphal period in the stubbles of rice plants. The adult appers from mid October to May and again from July to September. The lst egg-sacs are made in early June in the stubbles of rice plants and the clods of soil, and during the period from mid August to early October in the rice stubbles. After the rice transplantation, this spider inhabits around the rice stubbles. A female of the lst generation makes about 7 egg-sacs, and 120 eggs are deposited in one sac. The eggs hach in about 12 days in paddy field, and the development from egg to adult is completed in 75 days in female, 70 days in male. And they moult five times.
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  • Takeo YAGINUMA
    1973 Volume 25 Issue 1 Pages 16-22
    Published: 1973
    Released on J-STAGE: March 29, 2007
    JOURNAL FREE ACCESS
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  • Haruki OSAKI
    1973 Volume 25 Issue 1 Pages 23-36
    Published: 1973
    Released on J-STAGE: March 29, 2007
    JOURNAL FREE ACCESS
    Chlamydia-like microorganism was observed not only in the cytoplasm but also within the intracytoplasmic inclusions of hepatopancreas cells of the spider, Coras luctuosus. The reticulate body, which bears a resemblance to that of members of the genus Chlamydia, is generally spherical and approximately 370 to 800mμ in diameter; its cytoplasm contains ribosome-like particles as well as fine DNA-like fibrils, and is bounded by a double-layered cell wall and a cytoplasmic membrane. The frequent occurrence of pairs or clusters of reticulate bodies and of profiles with symmetrical constriction, suggests that the reticulate bodies multiply by fission. Maturation process of the cell is accomplished by condensation of DNA-like fibrils. The elementary body is spherical, from 320 to 360mμ in diameter, with an eccentrically placed electron-dense nucleoid. In addition, four kinds of unusual parasites, which are undoubtedly cellular and procaryotic, are found only in the spider infected with the chlamydia-like microorganism. The possible relations of these parasites to the chlamydia-like microrganism are discussed.
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  • Somnath BANERJEE
    1973 Volume 25 Issue 1 Pages 37-40
    Published: 1973
    Released on J-STAGE: March 29, 2007
    JOURNAL FREE ACCESS
    The population density of acari specially oribatids increases in the months of July and August (monsoon months) when the nitrate content of the soil also increases. It is recorded that the population density of Bacteria, Actinomycetes and fungi increases during monsoon months.
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