Acta Arachnologica
Online ISSN : 1880-7852
Print ISSN : 0001-5202
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16 巻 , 1 号
選択された号の論文の4件中1~4を表示しています
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  • 吉倉 真
    16 巻 (1958 - 1959) 1 号 p. 1-7
    公開日: 2008/12/19
    ジャーナル フリー
    Typopeltis stimpsonii is found in the southwestern part of Kyushu, where it occurs either in graveyards or in cultivated fields on hillsides and hides by day under stones. The breeding season ranges from late June to early July. The female lays eggs within a burrow, which is often found in the earth beneath a stone (fig. 1). When the eggs are laid, a viscid fluid flows from the genital opening, and an egg sac is made from it. The eggs are spherical, or broadly oval, 3-3. 5mm in diameter, white in color, and are placed in the sac. With the progress of egg-laying, the sac becomes bulged with eggs. The number of eggs varies from 32 to 40. The completed sac is somewhat horseshoe-shaped, 18-20mm in length, 20-22mm in width, 8-10mm in thick, and is attached to the sternal plate of the third abdominal segment of the mother (fig. 2). At first the sac is transparent, but, later, becomes tinged with reddish brown. About a month after the egg-laying, the hatching of the young and the first true molt occur simultaneously. At this time the mother rubs the egg sac repeatedly against the ground, thus the sac is broken. The youngs of the first postembryonal stage measure about 7mm in body length (fig. 2). They mount the back of the mother and stay there for a few days. Then the youngs leave the mother and hide in the ground, where they will undergo the second molt. The molting appears to occur once a year, usually in summer, and the female molts at least six times before becoming mature.
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  • 高島 春雄
    16 巻 (1958 - 1959) 1 号 p. 8-9
    公開日: 2008/12/19
    ジャーナル フリー
  • 八木沼 健夫
    16 巻 (1958 - 1959) 1 号 p. 10-17
    公開日: 2008/12/19
    ジャーナル フリー
    No Cyrtophora spider has been recorded till now in Japan. However, according to the writer's examinations, it was found that two species of Cyrtophora actually exist.
    1. Cyrtophora ikomosanensis (BOESENBERG et STRAND) 1906
    This species was first desdribed as Aranea ikomosnensis by BOESENBERG and STRAND. But it should be undoubtedly Cyrtophora, and has many resemblances to Cyrtophora moluccensis (Dol.) in shape and colour. The web making habit is also similar to the latter, i.e. it makes a large dome-web, about 30-80cm in dia-meter, consisting of many small wide meshes (1.5mm×2mm), which can be con-sidered as a modification of an orb-web. But the spirals have not sticky drops. The radial threads increase towards the edge, so all the meshes are of same size. This web resembles to Linyphiid web at a glance, but in the structure, this is rather nearer to Nephila than to Linyphia.
    2. Cyrtophora exanthematica (DOLESCHALL) 1859
    This species hitherto been known as Cyclosa bifurcata Kishida (not Walck.) in Japan. But this is not Cyclosa, and its name should be rejected as a secondary homonym on account of existence of Cyrtophora bifurcata (WALCI ENAER) 1841. The writer has identified this species with Cyrtophora exanthematica. Abdomen narrow behind and bifurcated posteriorly. Anterior part of abdomen with weak humps projecting laterally at both sides. Dorsal surface with 6 pairs of muscle-impressions and many small granules scattered exanthematically as its name shows. Two white lines run from shoulder humps to the posterior bifurcated lobes. (no granules seen in male). The web is horizontal and consists of small meshes, like Cyrtophora ikomosanensis, and irregular webs are seen above and below the main web. The spirals are not sticky like the preceding species.
    The writer recognized the following two types in this genus of Japan.
    Group I (Euetria type)
    1. MOA square, both sides almost parallel. 2. Legs long, patella plus tibia shorter than metatarsus plus tarsus. 3. Posterior eye row almost straight, 4. Pro-tuberances on anterior part of abdomen conical. 5. Web is dome-shaped.
    Cyrtophòra ikomosanensis belongs to this group.
    Group II (Cyrtophora type)
    1. MOA trapezoid, wider in font than behind. 2. Legs snort and stout, patella plus tibia longer than metatarsus plus tarsus 3. Posterior eye row strongly recu-rved. 4. Pretuberances on abdomen poined laterally. 5. Web is horizontal. Cyrtophora exanthematica belongs to this group.
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  • Jun-ichi AOKI
    16 巻 (1958 - 1959) 1 号 p. 18-20
    公開日: 2008/12/19
    ジャーナル フリー
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