书城外语英国学生科学读本
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第59章 毛毛虫向前爬

1.All birds lay eggs.If the eggs are kept warm,after a certain time a little bird,just like the parent birds,comes out of each egg.

2.All insects also lay eggs.But these eggs donot produce perfect insects.Out of each tiny egg there comes a small,soft creature,which looks somewhat like a little worm,and is known asa maggot,a grub,or a caterpillar.

3.The eggs of flies produce maggots;the eggs of most beetles produce grubs;the eggs of butterflies and of moths produce caterpillars.Maggots have no legs,and it is not easy to tell which end of their body is the head.Grubs have either no legs at all,or at most six legs.

4.But caterpillars have not only six true legs;on the hinder part of their bodies they have a number of what we may call false feet-little fleshy things whichare very useful in helping the caterpillar to move about,or to hold on to the twigs of trees.

5.I should like you to keep some caterpillars.They will need looking after and feeding,but they will repay you for your trouble,if you watch their funny ways and the curious changes that they pass through.

6.For a few pence,you can buy a hundred silk-worms‘eggs.If you keep them in a warm place for a few days,they will change to caterpillars.These will then need to be fed with mulberry①leavesor lettuce②leaves.

7.Another way of getting caterpillars is to look for them on the under sides of the leaves of such plants as the nettle,the rose,and the hawthorn.You must feed these caterpillars on the leaves of the plant on which you found them;and as they are very greedy,they will want some fresh leaves every day.

8.The body of the caterpillar grows,but its skin does not grow.When the old skin becomes too tight,it splits down the back,and the caterpillar crawls out.A new and larger skin soon grows on its body.The caterpillar then eats up its old skin.

9.This happens about five times before the creature grows to its full size.Then it stops feeding,and its body changes into what is called a chrysalis.The silk-worm caterpillars wrap themselves round with a ball of silk called a cocoon while they are going through this change.Others cover themselves with ahard brown case of skin.

EGGS,CATERPILLAR,CHRYSALIS,AND MOTH

(卵、鳞翅目幼虫、蛹、蛾子)

①Mulberry,a tree found in warm countries,on the leaves of which silk-worms feed.

②Lettuce.a plant somewhat of the shape of a cabbage,used as a salad.

10.Then after a time the case or the cocoon breaks open,and a perfect insect (a butterfly or a moth)creeps out,ready to fly about and to lay some tiny white eggs.

11.Do you see the caterpillar’s small black head?It has a strong pair of jaws,and with them it eats every day a great many leaves.

Look also at the hairs on its back.These hairs have two uses.They prevent①birds from eatingthe caterpillar,for the bird does not like these hairs to stick inits throat;and,besides,if the caterpillar falls from a leaf to the ground,the hairs break②the fall,and keep it from being hurt.

SUMMARY

Caterpillars are produced from the eggs of butterflies and moths.Before it grows to its full size,the caterpillar changes its skin about five times.After that it stops feeding,and its body changes into a chrysalis.While undergoing this change,the silk-worm caterpillar wraps itself round with a ball of silk called a cocoon,and others have a hard brown case of skin.After a time this cocoon or case breaks open,and a perfect insect-a butterfly or a moth-creeps out,ready to fly about.

【中文阅读】

1.鸟儿都会下蛋。如果鸟蛋能保持温暖,过一段时间,长得很像爸爸妈妈的小鸟就会破壳而出。①2.所有的昆虫都会“产卵”,但这些虫卵可不会孵出成虫。每个细小的虫卵里出来的,都是软软的小动物,看上去像“小肉虫子”,英语的名字分别叫maggot,grub,caterpillar。

①Prevent,hinder;keep from doing.

②Break,lessen the force of.

3.苍蝇的卵孵出来的是maggot(也就是蛆);多数甲虫产的卵孵出来的是grub(鞘翅目幼虫);蝴蝶和蛾子产的卵孵出来的是caterpillar(鳞翅目幼虫)。蛆没有腿,也不容易看出来身子哪一端是脑袋。鞘翅目幼虫要么没有腿,要么最多有六条腿。

4.但是鳞翅目幼虫不只有六条真正的腿,在身体的后半边,还有一种叫“假脚”的东西--肉做的小小突起,这些东西很有用,能帮助幼虫到处爬,还能帮助它抓住小树枝。②5.小朋友,请你也养一些鳞翅目的幼虫吧!它们需要好好照顾,好好喂养,但是也会回报你的辛苦,如果你观察到它们有趣的生活,还有奇妙的变化。

6.几个便士就可以买到100颗蚕卵。把蚕卵放在暖和的地方,过几天,就会孵出幼虫,这些幼虫要喂桑叶和莴苣叶。

7.还有一种办法能捉到鳞翅目幼虫,就是到荨麻、玫瑰、山楂这些植物的叶子下面去找。在什么植株上找到的幼虫,就要用什么叶子来喂;这些幼虫很贪吃,每天都要吃掉一些新鲜叶子。

8.幼虫的身体会长大,但皮肤却不长大。旧的皮肤变得太紧了,就从背部裂开,幼虫会从旧皮里面爬出来,很快长出更大的新皮肤。然后幼虫就把旧皮吃掉了。③9.这个过程要重复大概五次,幼虫才能长到最大。然后幼虫就不吃东西了,身体变成了“茧”,英语是chrysalis。蚕的幼虫这样变化的时候,会把身体包在一个蚕丝做的球形壳子里面,这壳子叫“蚕茧”(cocoon)。其他种类的幼虫,则会用一层坚硬的棕色壳子,盖住自己的身体。

10.过了一段时间,壳子或者茧就会破开,一只成虫(蝴蝶或者蛾子)爬出来,准备翩翩飞舞,产下小小的白色虫卵了。④11.你看见幼虫的小黑脑袋了吗?幼虫有一对强壮的上下颚,用这对上下颚,每天都要吃掉很多叶子。⑤再看看背上的毛。这些毛有两个用途:可以保护幼虫不被鸟吃掉,因为鸟不喜欢这些毛扎在喉咙里;而且,如果幼虫从叶子上掉了下去,这些毛可以起到缓冲的作用,不让幼虫摔伤。⑥译注①这个说法不确切;小鸟有“早成型”和“晚成型”。早成型的小鸟,孵出来就跟父母差不多;但晚成型的小鸟,刚孵出来的时候,却不像成年鸟,它们身上没有羽毛,不会走路,需要父母照顾,比如咱们前面学到的鸽子。

②这种“假脚”学名是“腹足”,英语是proleg(s).鳞翅目幼虫的腹足一般有5对。腹足上长着“趾钩”,所以能用来抓住东西。

③新皮不是蜕皮之后才长出来的。幼虫在蜕皮之前,其实已经长成了薄薄的新皮,但蜕皮之后,新皮会吸收空气或水来增大体积。这时候幼虫的肌肉还保持收缩状态,之后身体才会增大。我们就按照幼虫蜕皮的次数,来计算它的年龄。

④蚕蛾是典型的结茧的鳞翅目昆虫。大多数蝴蝶是不结茧的。

⑤月字旁的“腭”和页字旁的“颚”是一对异体字,目前还没有清楚地界定两者在什么场合使用。本书的使用方法是:对于脊椎动物使用月字旁的“腭”,对于昆虫则使用页字旁的“颚”。

⑥毛的主要作用是防御天敌的袭击。这个“防摔”的说法是有点可疑的,因为有很多种类的幼虫缺乏体毛,但掉在地上也不会受伤。

THE BEAUTIFUL BUTTERFLY