Explain the external characters of a typical insect which belong to non chordate phyla?

The body of insect is divisible as head, thorax and abdomen. The head has eyes, antennae and mouth parts. The mouth parts are associated with the mouth. Thorax consists of prothorax, mesothorax and metathorax. Each segment has a couple of legs and so there are six legs in an insect. So they are known as hexapod. They have 4 wings which arise from mesothorax and metathorax respectively. They are known as anterior and posterior wings. The abdomen has 10 segments without any legs. They have a couple of anal cerci which arise from the posterior part and bear an anus. There are a couple of spiracles which lead to trachea. There are different groups of insects which include the insects without metamorphosis, insects with gradual metamorphosis, insects with incomplete metamorphosis, and insects with complete metamorphosis. The development of insects without metamorphosis is known as ametabolous development. It includes the silver fish. They are the most primitive type and have no wings. They have egg, young and imago as their different stages of life history. The development of insects with gradual metamorphosis is known as paurometabolous development. They have egg, young and imago as their different stages of life history. The young resembles the adult in its way of life but differs in morphology. This type of development occurs in cockroaches, grasshoppers, termites, bed bug and lice. The development of insects with incomplete metamorphosis is known as hemimetabolous development. They have egg, young and imago as their different stages of life history. The young does not resembles the adult in its way of life and morphology. This type of development occurs in dragon flies. The development of insects with complete metamorphosis is known as holometabolous development. They have egg, young and imago as their different stages of life history. The young does not resembles the adult in its way of life and morphology. The pupa is transformed into an adult. This type of development occurs in butterfly, moths, mosquito, honey bees etc. The larva of moth and butter flies is known as caterpillar. The larva of houseflies is known as maggot and consequently the larva of beetles and mosquito is known as grub and wriggler respectively.
There are different mouth parts in insects such as biting and chewing, piercing and sucking, chewing and lapping, sponging and siphoning.