The group of insects undergoing this type of metamorphosis is also called Holometabola. In dragonflies the nymphs are aquatic while the adults are aerial and therefore this group is called Hemimetabola.Дў) Complete Metamorphosis or Complex or Indirect Metamorphosis: But there are rudiments of wings in the form of wing pad/ buds in these insects and hence these insects are called secondarily wingless insects. In few Exopterygota insects, the wings may be lost or may not develop at all, for example, head louse, bed etc. Such deviation from Hemimetabola is called aberrant Hemimetabola. A few insects like white flies and thrips on their developmental period, pass through a stage called incipient or false pupal stage (comparable to pupa of Holometabola) before emerging as an adults. The degree of metamorphosis is not the same in all Exopterygota. dragonflies, damselflies, grasshoppers, cockroach, crickets, aphids, jassids, bugs etc. There is no resting or transitional phase for transformation into adults e.g. The nymphs grow in size and shape by the process of moulting and the successive nymphs grow in size and shape by the process of moulting and the successive instars look more alike to adults. This wings development takes place externally and hence this group if insect is called Exopterygota. This type of metamorphosis is therefore, also called gradual metamorphosis. The wings develop gradually from a small wing pads in the nymphs to a fully developed functional wings in matured adults. Besides, nymphs are smaller in size and shape. The difference between the nymphs and adults is that the nymphs do not process wings and reproductive organs until they turn into full-grown adults. Similarly they have the same mode of life, feeding habits, food and habitat. These nymphs resemble their parents very much in their structure of body (mouth parts, simple and compound eyes, antennae, legs etc). The young ones on hatching from eggs are called nymphs. There are three stages in the life of these insectsвЂ™ viz.

Insects under this type complete their postembryonic development without assuming much striking morphological changes.

The group of the insects undergoing this type of metamorphosis is also called Hemimetabola.

1) Incomplete Metamorphosis or Direct or Simple Metamorphosis:

Stages of metamorphosis