Acta Arachnologica
Online ISSN : 1880-7852
Print ISSN : 0001-5202
ISSN-L : 0001-5202
Volume 24, Issue 1
Displaying 1-4 of 4 articles from this issue
  • Seisho SUZUKI
    1972 Volume 24 Issue 1 Pages 1-8
    Published: 1972
    Released on J-STAGE: March 29, 2007
    JOURNAL FREE ACCESS
    1. This paper is concerned with the discontinuous distribution in some Opiliones.
    2. Caddo agilis BANKS (Caddoinae) occurs disjunctively in Japan and in the north-eastern area of North America.
    3. Japanese Cladolasma parvula SUZUKI (Nemastomatidae) strikingly resembles the North American Dendrolasma mirabilis BANKS, both of which showing the distribution pattern of amphipacific disjunction.
    4. Crosbycus dasycnemus (CROSBY) (Nemastomatidae) so far known from the north-eastern area of North America is newly recorded from several localities of Japan. The populations of the both areas are so similar that no specific distinction is obtained.
    5. All the species discussed are regarded as survivors.
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  • Toshio UYEMURA, Takeo YAGINUMA
    1972 Volume 24 Issue 1 Pages 9-14
    Published: 1972
    Released on J-STAGE: March 29, 2007
    JOURNAL FREE ACCESS
    Araneus boreus n. sp.
    Holotype (_??_): Yukomanbetsu, Mt. Daisetsu, Hokkaido, 10-VII-1970, Y. Nishikawa, Y. Tarumi and A. Noto collectors.
    Total length 9.5mm; carapace 3.7mm long, 3.2mm wide; abdomen 7.0mm long, 6.3mm wide.
    Cephalothorax longer than wide, covered with white hairs on the brown ground. Head narrower than thorax (2:3), with parallel sides. A bottle-like black fleck is in front of the transverse median furrow, and eight pairs of small black flecks scattered around it. Cervical grooves convergent posteriorly, but their ends do not meet with each other. Median furrow evident. Eyes arranged typically as seen in other species of Araneus. Anterior eye row slightly recurved seen from front; posterior row procurved seen from above. Lateral eyes of both rows separated widely from middle eyes. Median ocular area wider in front than behind (3:4.5), as long as wide. Clypeus less than the half the length of median ocular area. Palp whitish green with a black ring fleck at the end of each segment. The apical segment black with many spines. Chelicera stout and black, having a conspicuous whitish green fleck furnished with white hairs on the base of its prosurface. Fang black. Four teeth on the promargin of fang furrow, three teeth on the retromargin. Maxillae yellowish white in the anterior half, black in the posterior half; their inner sides white and divergent anteriorly. Labium semicircular in shape, wider than long (34: 21), black with white anterior edge. Sternum long cordate, procurved in front, pointed behind, black with a yellow longitudinal fleck in the median line. Coxae and trochanters of legs similar to sternum in colour. Leg formula 1243. The measurements are shown on page 10. Abdomen globular, whitish green in colour, with a pair of bat-like black fleck and a black folium pattern. Both sides black. Venter black with two pairs of yellow round flecks near the spinnerets. The both sides grayish green. Spinnerets black. Epigynum with a long soft (not so strongly sclerotized) scape crooked at base.
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  • Uri GERSON
    1972 Volume 24 Issue 1 Pages 15-28
    Published: 1972
    Released on J-STAGE: March 29, 2007
    JOURNAL FREE ACCESS
    Ledermuelleria frigida HABEEB, a little-known, moss-feeding mite is redescribed in all its stages from specimens collected in southern Quebec. Morphological characters which occur in all stages of the mite are noted and afford the best features for its definition. Scanning electron micrographs are presented to illustrate some parts of L. frigida.
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  • Makoto YOSHIKURA
    1972 Volume 24 Issue 1 Pages 29-39
    Published: 1972
    Released on J-STAGE: March 29, 2007
    JOURNAL FREE ACCESS
    1. The embryonic and the early post-embryonic development of Ummidis fragaria (Ctenizidae) was studied on preserved and living materials.
    2. The embryonic development of Ummidia closely resembles that of other mygalomorphs.
    3. In about three weeks the eggs hatch and the prelarvae emerge. About two days after hatching they take the first molt and become the larvae. The larval stage lasts about four weeks and the larvae transform into the protonymphs. The early postembryonic development of Ummidia is very similar to that of Ischnothele (Dipluridae).
    4. In Ctenizidae, Dipluridae and Theraphosidae the larval stage consists of two phases: pL, L or L, pN, whereas in Atypidae only one phase, L. In the primitive spider, Heptathela also the larval stage is only one phase, L. From a point of view of comparative embryology, therefore, the Atypidae may be the most primitive among the mygalomorph spiders.
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