蜘蛛并非昆虫,在动物界中自成一类,属蛛形纲节肢动物门类的一纲。世界上约有3.5万～4万种蜘蛛,绝大多数对人类有益,它们是昆虫的敌人。其中比较有趣的有: 世界上最大的蜘蛛是南美洲的食鸟蛛,它以网来捕捉自投罗网的鸟类为食。食鸟蛛一般体长8厘米多,重50多克,如果把它身体伸直,4对步足向外延伸展开,体宽即达25厘米以上。1945年在巴西 Spiders are not insects, and they are self-contained in the animal kingdom. They are a class of Arachnoid arthropods. There are about 35,000 to 40,000 species of spiders in the world. Most of them are good for humans. They are the enemies of insects. Among the more interesting ones are: The world’s largest spider is the South American tortoise, which uses the net to capture the birds that feed it. Tarantula is generally more than 8 cm long and weighs more than 50 grams. If it stretches its body, four pairs of footsteps will extend outwards and reach a body width of 25 cm or more. 1945 in Brazil