Holometabolous insects have immature forms (larvae) that are very different from adults. Larvae are "feeding machines", adapted mostly for consuming food and growing in size.  They become larger at each molt but do not acquire any adult-like characteristics. When fully grown, larvae molt to an immobile pupal stage and undergo a complete transformation. Larval organs and appendages are broken down (digested internally) and replaced with new adult structures that grow from imaginal discs, clusters of undifferentiated (embryonic) tissue that form during embryogenesis but remain dormant throughout the larval instars. The adult stage, which usually bears wings, is mainly adapted for dispersal and reproduction.

Eggs, depending upon species, vary in number, size, shape and coloration. You'd need a magnifying glass to examine eggs of many moths. Larger species such as some of the Giant Silkmoths may have eggs several mm in diameter. Eggs may be laid singly or in masses of 100 or more. There is usually a high degree of synchrony in the hatching of a clutch of eggs (taking from a few days or weeks to several months in the case of species who overwinter in the egg stage). At eclosion or hatching the egg remains are usually eaten by the first instar larvae.

1.  Cocoon containing corpse of a Western Tussock Moth pupa and, beside it, the puparium of a parasitoid Tachinid Fly.
2.  A well crafted silk cocoon of the Cecropia Moth, Hyalophora cecropia.
3.  A Bagworm Moth case used for protection during the larval phase, it serves also as a pupation site. Wingless females never leave the  case. In this instance a male has eclosed to adulthood leaving behind the puparium or exuvium now projecting from the tip of the case. It  will locate a female when she releases a pheromone attractant, and mate with her through a small opening in her protective case.
4.  Numerous micromoths are known as casebearing moths and utilize diversely designed cases in which to pupate. This is the Pistol  Casebearer Moth, Coleophora atromarginata, named after the shape of its case.
   
   

5.  Cocoon of the Southern Tussock Moth, Dasychira meridionalis, richly lined with the caterpillar's hairs added to the silken enclosure.
6.  Wingless female of the Live Oak Tussock Moth, Orgyia detrita with her eggs on top of the cocoon from which she eclosed. Here we have  three life stages in a single photo. She will probably cover the egg mass with a frothy protective coating.
7.  Some species use little or no silk to conceal their pupation site, especially when it is their custom to pupate in leaf litter. This is the  Bella Moth, classified here as part of the complex species Utetheisa ornatrix.
8.  Frequently, skin of the last instar caterpillar is found in the cocoon with the pupa. In this case the caterpillar of a Giant Leopard Moth,  Hypercompe scribonia did not incorporate its body hairs into the cocoon. The brown puparium seen here will blacken prior to eclosure.
   
   

9.   Pupae Jewels found in leaf litter. Laurel Shinx Moth in Ontario.
10.   Rustic Sphinx Moth in Florida.
11.   Ello Sphinx Moth in Florida.