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''Phaeacius'' is a spider genus of the family Salticidae (jumping spiders), found in sub-tropical China and between India and the Malay Peninsula, including Sri Lanka, Sumatra and the Philippines. Although other spiders can jump, salticids including ''Phaeacius'' have significantly better vision than other spiders, and their main eyes are more acute in daylight than a cat's and 10 times more acute than a dragonfly's. The main eyes focus accurately on an object at distances from approximately to infinity, and in practice can see up to about . While most jumping spiders are active hunters, ''Phaeacius'' is unusually sedentary, generally resting in its unusual flattened pose for hours or days on logs, tree barks, pieces of wood or any other solid surface, where it is very well camouflaged. Its preferred prey is moths and other insects, and jumping spiders. Insects can usually move around an inactive ''Phaeacius'', or even over its body, but if the insect moves between the spider's first pair of legs, ''Phaeacius'' lunges extremely quickly to bite the prey. Sometimes ''Phaeacius'' takes a more active approach, especially if without prey for a week or more. ''Phaeacius'' does not enter webs voluntary, and moves away if it touches one accidentally. It can bite through the threads and pull strongly with its legs, but cannot escape from very sticky webs. The closest relatives of ''Phaeacius'' are in the genus ''Holcolaetis'', and the next closest genera are ''Portia'' and ''Spartaeus''. ==Body structure== }} Spiders are chelicerates, which differ from other arthropods in that the usual body segments are fused into only two tagmata, the cephalothorax and abdomen.〔 Jumping spiders have a distinctive rectangular carapace. All spiders' abdomens bear appendages that have been modified into spinnerets that extrude silk from up to six types of silk glands within their abdomen. The cephalothorax and abdomen are joined by a small, cylindrical pedicel, which allows the abdomen to move while spinning silk. While most jumping spiders do not build webs to catch prey, they use silk for other purposes,〔 including moulting and laying eggs. The whole body of ''Phaeacius'' is long, and notably flattened, including the carapace,〔 while the carapaces of some other groups are raised.〔 The cepholothorax of ''Phaeacius''′ is relatively long, and the highest point is a little behind the last pair of eyes. ''Phaeacius'' is very well camouflaged;〔 for example, ''P. malayensis'' has a body with dull grey and brown markings that resemble the surface of tree trunks in the rainforest.〔〔 Jumping spiders generally have large forelegs and short, powerful back legs,〔 and can leap up to 50 times their own length by powerfully extending the third or fourth pairs of legs. In spiders and other chelicerates, there is only one pair of appendages before the mouth,〔 and in spiders these are modified into fangs that inject poison into the prey.〔 Behind the mouth is a pair of pedipalps ("palps" for short),〔 and those of male spiders are quite large and are used for displaying and mating.〔 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「Phaeacius」の詳細全文を読む スポンサード リンク
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