 hollow metabolus metamorphosis, first the contents, the definition of hollow metabolus metamorphosis, then the egg stage, larval stage, pupa stage and the adult stage. First the hollow metabolus metamorphosis. So, hollow metabolus metamorphosis is also called as the complete metamorphosis. So, it is the process in which there are four distinct stages of metamorphosis are present. So, hollow metabolus means it is the complete metamorphosis. This is the type of metamorphosis in which the animal passes through all the stages of metamorphosis. Normally the complete metamorphosis can that there are four stages. It is the egg stage, it is the larval stage, pupa stage and the adult stage. So, if we talk about hollow metabolus metamorphosis, most of the insects. In a gram, insects is the largest group of animals. Animals have about 90% of insects. Now, the insects have more than 88% insects, they undergo complete metamorphosis. What is the benefit of complete metamorphosis? Complete metamorphosis through the animals, it performs its different activities at different stages of development. What will it do on different stages of development? It will perform different physical activities. For example, growth. There is a separate activity for growth. There will be a separate stage for differentiation. There will be a separate stage for sexual activity and reproduction. For example, the larval stage is for growth. In this way, the intensive different types of differentiation of the cells that will take place during the pupa stage. For sexual reproduction, there is the adult stage. It means the animals through metamorphosis, it has divided its activity into different groups, different stages. The activities of different stages have been divided. The benefit is that it will not interfere with the activities of the next stage. The activities do not interfere with each other. When there is growth, there is differentiation. When there is reproduction, there will be no growth or differentiation, just reproduction. As we have already discussed, there are four stages in complete metamorphosis. That is the egg stage, larval stage, pupa stage and the adult stage. For example, we have a lot of them. We have mosquitos. They undergo complete metamorphosis. Butterflies undergo metamorphosis. These are the different types of insects. Most of the insects undergo complete metamorphosis. In this diagram, there are four steps of complete metamorphosis. The generalized diagram has four steps. We have discussed about metamorphosis. The first stage is the egg stage. After the egg stage, the second stage of metamorphosis is the larval stage. The larval stage is the feeding stage. The third stage is the pupa stage. And the fourth stage is the adult stage. The fourth stage is the metamorphosis. They are representing the complete metamorphosis. In the development of the animals, these four stages will be present. They will be having hollow metabolism. Metamorphosis are complete metamorphosis. The complete metamorphosis in the first stage is the egg stage. The egg stage is the stage in which the development is happening within the egg. After the fertilization, the developmental process starts. In some cases, egg fertilization is not done in the case of parthenogenesis. And the development starts as well. Whether it is fertilized or unfertilized, the development will start on the first step. There will be cleavage, blastulation, and gastrulation. The initial developmental stages are completed within the egg. The egg is completed within the egg. This stage is called the egg stage. Early embryonic development is happening on the egg stage. Most of the insects have a very short egg stage. Most of the insects have a short egg stage. But some of the insects may have a diapause. Diapause can cause a gap. Especially when they are seasoned, the environmental conditions are not good. If the environmental conditions are not good, then the diapause will cause a gap. The development will rest for some time so that further development can be started on good conditions. The second stage is the larval stage. When the development is completed within the egg, from the egg, the larvae will emerge. An larvae will come out of the egg. Larvae is a worm-like animal, which is very active. It feeds. Larvae is known as a motile. It feeds. Because of its feeding, the larvae store energy inside them. Which will be used in further development. Some of the properties of larval are that larvae never have wings. Larval stages do not have wings. The rest of the structures remain the same. They are having simple eyes. You know that the insects have compound eyes. Adult insects have compound eyes. But when the larvae is infected, it will be having simple eyes. The difference between compound and simple eyes is that there are many lenses in the compound eyes. The simple eye has only one lens. There are many sub-stages in the larval stage. Small larvae, big larvae, big larvae, big larvae, and big larvae. We call every larval stage an in-star. When we say that the first in-star of the larvae comes out of the egg, then the second in-star, then the third in-star. The difference is that the size increases, which is undergoing the process of molting. The molting is done by moving the first, second, third and fourth in-star. The third stage of development is the pupa stage. To talk about the overall of the pupa stage, it is an inactive stage. When the larvae is inactive, it will pass through such abrupt metamorphosis. The larval stage is the feeding stage, and the pupa stage is the stage of differentiation. There is differentiation between abrupt morphological and physiological changes. As a result, during abrupt changes, the pupa develops a casing around itself. If the pupa develops a casing, a cocoon develops, the larvae will start converting into adults during the pupa stage. So, most of the pupa, they do not move. If we look at the pupa, they are inactive when we say they are not moving. However, some of the pupa stages, they may have some motility. So, when the pupa stage is completed, we will have the adult stage. The adult stage from pupa and adult insect emerge. An insect comes out, which is an adult, and all its morphology and physiological functions are working. The main identity of adult is that it is reproductively functional. The reproductive organs of it are functional. It can reproduce. When there are adults, they do not feed. In insects, they do not feed. They are just produced for reproduction process. They reproduce, and then die out.