The transfer of larva into adults through drastic change is called metamorphosis.

Metamorphosis is a biological process that refers to the transformation of an organism from its larval stage to its adult stage. This process involves a series of drastic changes in the organism's body structure, physiology, and behavior. Metamorphosis is commonly observed in insects, amphibians, and some other animal groups.

Stages of Metamorphosis:
Metamorphosis generally consists of several distinct stages, which may vary depending on the organism. However, the two main types of metamorphosis are incomplete metamorphosis and complete metamorphosis.

1. Incomplete Metamorphosis:
Incomplete metamorphosis is seen in insects such as grasshoppers, dragonflies, and cockroaches. It involves three stages:

- Egg Stage: The life cycle begins with the deposition of eggs by the adult insect.

- Nymph Stage: The egg hatches into a nymph, which resembles a miniature version of the adult insect. The nymph goes through several molts, shedding its exoskeleton and growing larger each time.

- Adult Stage: Once the nymph reaches its final molt, it emerges as a sexually mature adult insect.

2. Complete Metamorphosis:
Complete metamorphosis is seen in insects such as butterflies, beetles, and bees. It involves four stages:

- Egg Stage: The life cycle begins with the deposition of eggs by the adult insect.

- Larva Stage: The egg hatches into a larva, also known as a caterpillar or grub. The larva is typically worm-like in appearance and undergoes rapid growth by feeding on food sources.

- Pupa Stage: After a period of feeding and growth, the larva enters the pupa stage. During this stage, the larva undergoes a complete reorganization of its body structure inside a protective casing called a pupa or chrysalis.

- Adult Stage: Inside the pupa, the larva undergoes a complex transformation known as metamorphosis, during which its body tissues are broken down and reassembled into the adult form. Finally, the adult insect emerges from the pupa, fully developed and capable of reproduction.

Significance of Metamorphosis:
Metamorphosis is a critical process for the survival and success of many organisms. It allows the organism to adapt to different ecological niches and exploit new resources. For example, the larval stage of butterflies and moths feeds on plant matter, while the adult stage feeds on nectar, allowing them to take advantage of both food sources.

In conclusion, metamorphosis is the transformation of an organism from its larval stage to its adult stage. This process involves a series of distinct stages and is essential for the survival and adaptation of many organisms.