蜘蛛为什么应该是我们的朋友呢，你也许会纳闷？
Why, you may wonder, should spiders be our friends?
因为它们消灭了大量昆虫，而昆虫中有一些是人类最大的敌人。
Because they destroy so many insects, and insects include some of the greatest enemies of the human race.
如果没有以昆虫为食的动物为我们提供保护，昆虫就会让我们无法在这个世界上生存；它们会吞食我们所有的庄稼，杀死我们的禽群和兽群。
Insects would make it impossible for us to live in the world; they would devour all our crops and kill our flocks and herds, if it were not for the protection we get from insect eating animals.
我们确实欠了那些以昆虫为食的鸟类和兽类很多，但它们全部加在一起消灭的昆虫，也只不过是蜘蛛所消灭数量的极小一部分。
We owe a lot to the birds and beasts who eat insects but all of them put together kill only a fraction of the number destroyed by spiders.
此外，与其他一些食虫动物不同，蜘蛛从不对我们或我们的财物造成任何伤害。
Moreover, unlike some of the other insect eaters, spiders never do the least harm to us or our belongings.
蜘蛛并非昆虫——尽管许多人这样认为——甚至与昆虫也没有什么近亲关系。
Spiders are not insects, as many people think, nor even nearly related to them.
几乎只需一眼就能分辨出两者的区别，因为蜘蛛总是有八条腿，而昆虫从来不超过六条。
One can tell the difference almost at a glance, for a spider always has eight legs and an insect never more than six.
有多少蜘蛛在为我们从事这项工作呢？
How many spiders are engaged in this work on our behalf?
一位研究蜘蛛的权威人士在英格兰南部的一片草地上对蜘蛛进行了普查，他估计一英亩的土地上有超过 225 万只蜘蛛；也就是说，一个足球场上大约有 600 万只各种各样的蜘蛛。
One authority on spiders made a census of the spiders in a grass field in the south of England, and he estimated that there were more than 2,250,000 in one acre; that is something like 6,000,000 spiders of different kinds on a football pitch.
蜘蛛一年中至少有半年的时间都在忙着捕杀昆虫。
Spiders are busy for at least half the year in killing insects.
要猜测它们究竟捕杀了多少昆虫，即便是最大胆的估计也无从做起，但它们确实是贪食的动物，绝不满足于一天只吃三顿。
It is impossible to make more than the wildest guess at how many they kill, but they are hungry creatures, not content with only three meals a day.
据估计，英国蜘蛛在一年内消灭的所有昆虫的总重量，将超过全国所有人的体重之和。
It has been estimated that the weight of all the insects destroyed by spiders in Britain in one year would be greater than the total weight of all the human beings in the country.