キムラグモの精巣内精子は,幅約6μの球乃至楕円球状の細胞質膨大部と,これから突出した長さ20～25μのスピロヘータ状の頭部とから成り,先端に特殊な尖体複合体を具えている.尖体は胞状で,その後側面は先端に向って深く陥入して内腔をつくり,ここに尖体繊維が挿入されている.尖体胞は先端部を除くと電子密度の高い顆粒物質で満たされている.尖体胞の内腔から後方に伸び出した尖体繊維は,核の周囲にラセンを形成していて,核膜起原の鞘によって包まれている.核の後端近くの陥入部には1個の中心粒があり,これから出た1本の長い鞭毛は,細胞質膨大部の周縁に3～4回とぐろを巻いている.鞭毛中間部はミトコンドリア鞘に包まれている.動植物を通じて鞭毛あるいは繊毛の横断面が普遍的に9+2型であるのに対し,キムラグモの精子鞭毛は9+3型,つまり,9対の周囲束と3本の中心微小細管とで構成されている.細胞質膨大部には giant body, 膜に包まれたグリコーゲン顆粒群,脂質及び核膜に由来したものと考えられる膜様構造物等が含まれている.

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従来北アメリカ固有属とされていたヒメグモ科 Stemmops (オチバヒメグモ属)の一種が日本に広く分布することが判明し,新種と認めて記載した.各地の落葉下などで採集されている. 模式標本以外の既地産地は次の通りである.(採集者敬称略)
宮城県金華山島, 22-XII-'68; 西川喜朗;東京都八王寺市, 26-IV-'68, 23-XI-'67, 新海栄一;玉川, 19-V-'69, 小林久後;高尾山, 28-V-'60, 西川;静岡県静岡市, 12-VI-'65岩崎光宏;安倍郡梅ケ島, 27-V-'69, 西川;岐阜県, 30-III-'69大江秀雄;奈良県当麻, 13-IV-'69, 西川;大阪府犬鳴山, 26-V-'68, 西川;岩湧山, 27-X-'68, 25-V-'69, 西川;太子, I-IV-'69西川;茨木, 14-VI-'68, 26-XI-'68, 西川;枚岡, 8-VI-'69, 西川;兵庫梁氷上, 29-V-'68,田中穂積;岡山県蒜出, 7-VII-'68, 西川.京都府,西川.群馬県;沼田, I～VII, '68, 武井武一

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Two species of beautifully coloured araneine spiders regarded hitherto as different are often found in the northern part of Japan; one is called Akaonigumo or Red Araneus and the other Daidaionigumo or Orange Araneus. The former has long been identified with Araneus quadratus CLERCK and the latter with Araneus pinguis (KARSCH) in this country.
The writer, however, has had some doubt about the justness of this identifica-tion, in that the red species can be found more in accord in its characters with the description of Araneus pinguis than with that of Araneus quadratus. Recently, through the kindness of Dr. M. Grasshoff and Dr. H. W. Levi, he has been given an oppor-tunity to examine some typical specimens of European Araneus quadratus. As a result of his comparative study, he has now come to a conclusion that the red species (Akaonigumo) has hitherto been wrongly identified with Araneus quadratus and that both speiders, red and orange (Akaonigumo and Daidaionigumo), can actually be referred to Araneus pinguis.
So far as its shape and structure of male palp (embolus, conductor, median apophysis and terminal apophysis) and those of female epigynum (scape and posterior lamellae) are concerned, Araneus pinguis is clearly distinguishable from Araneus quadratus, but it must be admitted on the other hand that the former has some notable affinity with the latter, too. Consequently, it is considered highly possible that Araneus pinguis may be either a geographic variation or a subspecies derived from a common ancestral stock.
For the time being, however, the writer still prefers to regard Araneus pinguis as an independent species for the following reasons.
1. It is not definitely known yet whether Araneus quadratus has varied with a cline across Siberia or its distribution is cut off somewhere on the continent.
2. There is much difference in sexual organs between Araneus pinguis and Araneus quadratus, so that the former seems to be far above the level of a subspecies of the latter in its characteristics.
3. The species reported as Araneus quadratus from the eastern part of Siberia (Amur and Kamchatka) may also be Araneus Pinguis. This is because the species from Manchuria and Sakhalin were found identifiable as the same species with Japanese one on the writer's examination.
After all, the comparative study of species, European, Siberian and Japanese, is very important, in order not only to give each respective one the correct specific name but also to research the variation, especially the speciation caused by geo-graphic isolation in such a vast area. The key to the solution of all these pro-blems, therefore, may possibly be found from the more profound and detailed study of the Siberian species.

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