What is reproduction?

A process by which living things produce more of their kinds.
 

Why do animals reproduce?

Animals reproduce so that their races do not die out.
 

How do animals reproduce?

• By laying eggs
• By giving birth to babies

The life cycle of egg laying animals consist of 2, 3 or 4 stages.

Butterflies belong to group Insecta and lay eggs.  They pass through four stages in their life cycle.

Egg > Caterpillar > Pupa > Butterfly. 

Now let's learn about the different life stages of a butterfly.
 

The Egg stage 

The eggs of butterfly are tiny and have a variety of shapes. The female butterfly lays the eggs on the leaves of the plants. After 6-7 days a worm like creature hatches out of the egg which is light green or yellow in colour.

The Larva stage 

It is tiny worm like known as baby caterpillar but does not undergo moulting (it's the process of shedding of skin several times before growing into an adult). 
 

The Caterpillar stage 

This is the active stage. The larva eats leaves and grows to a tremendous amount. This fully grown larva is called a caterpillar which has six real legs and a number of extra prolegs.It is the young one of a butterfly and does not resemble its parents. 

The Pupa stage 

This is called the resting stage. The caterpillar first spins a cocoon around its body and also fastens itself to a plant with a silk thread. The caterpillar which is inside the pupa changes into a butterfly. Generally pupas camouflage themselves to hide from predators. 
 

The Butterfly stage 

In this stage the baby butterfly emerges from the pupa and soon is transformed into an adult butterfly. 
 

Metamorphosis

Insects and butterflies change in form in their development from egg to adult. The different instars are not alike, this process is called metamorphosis

In a nutshell we can say that a Butterfly passes through four stages in its life cycle. Usually it lays eggs on a leaf. When the eggs hatch a small larva emerges and crawls out. This larva of a butterfly is called a caterpillar which starts eating the leaf and grows This is the active stage. During its life it moults a few times. Each time it becomes bigger. Soon it changes into a pupa. This pupa may be hanging on the plant in a small loop of silk. And after a few weeks the pupa turns into a beautiful adult butterfly.
 

Below is given the complete metamorphosis stage in which the wings develop internally during the larval stage. The larval stage looks very different from the adult stage. There is a pupal stage which usually is inactive between the last larval stage and the adult stage.