Ghost spider - Ghost spider

A general term for the family Pholciformes in the order Araneae of the phylum Arthropoda, or one of the spiders within that family. Spiders in this family are generally small with thin, long, weak legs. Their bodies are usually translucent gray. Many live indoors, spinning irregular, shelf-like webs in the attic or in the corners of dimly lit rooms. They were named 'pholciformes' because of their shape, color, and where they live.

The house ghost spider Pholcus phalangioides lives in houses all over the world. Its body length is 7 to 8 mm. It spins a large shelf-like web, which is often left up, ruining the house's appearance and making it seem unclean, but it does catch indoor pests. Most of the webs seen in old abandoned houses in movies are those of this spider. When it senses danger, it spins its body around to intimidate. Another indoor spider is the small Simon ghost spider Spermophora senoculata , which can be found under eaves or at the back of drawers (a species common throughout the world). At the end of 1982, it was discovered that the house ghost spider Crossopriza lyoni , which is found in India, China, Southeast Asia, and the Ryukyu Islands in Japan, had become established in houses in Aichi Prefecture, but this is thought to be the result of human distribution. The side of the abdomen of this species is triangular. In the wild, there is the ghost spider Pholcus crypticolens , and in caves, there is the Akebono ghost spider Spermophora akebona . In the Ryukyu Islands, there are the false ghost spider Smeringopus pallidus and the tropical ghost spider Physocyclus grobosus .

[Takeo Yaginuma]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

節足動物門クモ形綱真正クモ目ユウレイグモ科の総称、またはそのなかの1種。この科のクモは一般に体が小さく、脚(あし)が細くて長く、弱々しい。体色はたいていは半透明の灰色。屋内にすむものが多く、天井裏や薄暗い部屋の隅などに不規則な棚状の網を張る。形や色から、またすむ場所からユウレイグモと名づけられた。

　イエユウレイグモPholcus phalangioidesは世界中の家屋にすむ。体長7、8ミリメートル。大きい棚状の網を張り、また網を張りっぱなしにするので美観を損ない、不潔感を与えるので嫌われるが、屋内害虫を捕食してくれている。映画などの古い廃屋に出てくる網はたいていこのクモの網である。身の危険を感じると体をぐるぐる回して威嚇する。同じく屋内性のもので縁の下や引出しの奥などに小形のシモンユウレイグモSpermophora senoculataがいる（世界共通種）。1982年（昭和57）の末に、インド、中国、東南アジア、日本では琉球(りゅうきゅう)諸島に分布するオダカユウレイグモCrossopriza lyoniが愛知県の人家に定着していることがわかったが、これは人為分布の結果と思われる。この種の腹部の側面は三角形である。野外にはユウレイグモPholcus crypticolens、洞窟(どうくつ)にはアケボノユウレイグモSpermophora akebonaがいる。南西諸島にはユウレイグモモドキSmeringopus pallidusやネッタイユウレイグモPhysocyclus grobosusがいる。

［八木沼健夫］

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