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''Eucteniza'' ( ) is a genus of trapdoor spiders in the family Euctenizidae containing at least 14 species occurring in Mexico and the southern United States. Species are distinguished by a softened rear portion of the carapace, and males possess large spines on the first two pairs of walking legs that are used to hold females during mating. Like other trapdoor spiders they create burrows with a hinged lid, from which they await passing insects and other arthropods to prey upon. Many species are known from only one or two localities, or from only male specimens. More species are expected to be discovered. ''Eucteniza'' is closely related to spiders of the genera ''Entychides'' and ''Neoapachella''. ==Description== Members of ''Eucteniza'' reach up to in body length (not including the legs), which is relatively large to very large among spiders. The cephalothorax (the anterior body segment bearing the eyes, mouthparts, and legs) is oval, slightly longer than wide, and slopes considerably towards the rear when viewed from the side. The rear third of the carapace (the upper surface of the cephalothorax) is relatively soft, and is distinctly lighter in coloration. The carapace is often devoid of hairs, and in some species fringed with black bristles. The eight eyes are not elevated and are arranged in two rows in a rectangular area: the hind row is recurved, or slightly curved upwards (as in a bowl or shallow U), while the anterior row is slightly procurved (slightly curved downwards, as in an inverted bowl). ''Eucteniza'' spiders are colored in various shades of brown, with males generally appearing a dark reddish-brown. The jaws (chelicerae) are dark brown. The abdomen sometimes has a dark brown blotch on the upper surface.〔〔 Measurements of most species only refer to the cephalothorax, which is less variable than the abdomen: recorded cephalothorax lengths range from in ''E. huasteca'' to in ''E. relata''.〔 Eucteniza relata lateral.jpg|Side view of cephalothorax, third leg removed Eucteniza legs.jpg|Female leg 1 (left), and male legs 1 and 2 with tibial mating claspers In males, the tibiae (5th leg segments) of the first and second walking legs are swollen or enlarged in many species. Additionally, males possess one or two prominent spines, known as "mating claspers" on the first and second tibiae; related genera possess claspers on the first pair of legs only. The size, number, and arrangement of these spines varies between species. Females have a double-toothed groove that the fangs recede into, unlike that of any other euctenizid genus. Both sexes also possess "preening combs", rows of stiff bristles on the rear legs.〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Eucteniza」の詳細全文を読む スポンサード リンク
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