Class Insecta - Insects

phylogenetic arrangement of major extant taxa based on latest molecular data shown in(1)

Latin insectum, pl. insecta "cut into, cut up" (refers to body segmentation), a literal translation of Greek entomos (εντομος)

Anatomy

See Glossary for terminology.

worldwide and throughout North America (NB: aquatic marine forms conspicuously absent)

There are two prominent types of life cycles among the insects:

1-Hemimetabolous insects (e.g., dragonflies, mayflies, true bugs, grasshoppers) undergo gradual, or incomplete, metamorphosis. Immature stages (usually called nymphs) go through a series of molts, gradually assuming an adult form. Since the wings develop on the outside of the body, these groups are called exopterygotes. Some orders have immature stages that are aquatic. These possess specialized structures for aquatic life, such as gills, and are called naiads, or larvae.

2-Holometabolous insects have a four-stage life cycle: egg, larva, pupa, and adult (imago). The following orders of insects are holometabolous:

They form a group referred to as Endopterygota or Holometabola.

All the winged insects (including those who have lost their wings over the course of history) constitute a large taxon called Pterygota (sometimes treated as a subclass).

Pterygota orders listed alphabetically

*may be lumped with Cockroaches & Termites