Insects, Spiders, Centipedes, Millipedes
There are three types of pupae: obtect, exarate or coarctate.
However, overall, most individuals are female, which are produced by fertilization.
Air enters the insect through a few openings spiracles in the exoskeleton, and makes its way to all areas of need by way of branching tubes, which permeate the body.
A narrower circumscription restricts insects to those hexapods with external mouthparts, and comprises only the last three groups in the table.