Pterygota

Pterygota ( ) is a subclass of insects that includes all winged insects and groups which lost them secondarily.

The name Palaeoptera (from Greek ( 'old') + ( 'wing')) has been traditionally applied to those ancestral groups of winged insects (most of them extinct) that lacked the ability to fold the wings back over the abdomen as characterizes the Neoptera. The Diaphanopterodea, which are palaeopteran insects, had independently and uniquely evolved a different wing-folding mechanism. Both mayflies and dragonflies lack any of the smell centers in their brain found in Neoptera. Their midgut epithelium has a dual origin: the anterior and posterior regions develop through cellular differentiation, while the

Metapterygota is a clade of winged insects containing order Odonata and Infraclass Neoptera. They share morphological characteristics of a loss of caudal filaments and a subimago stage. Genetically the clade is supported by similarities in the mitochondrial genomes.

The Paleodictyopterida or Palaeodictyopteroidea are an extinct superorder of Palaeozoic beaked insects, characterised by unique mouthparts consisting of 5 stylets. They represent the first important terrestrial herbivores, and the first major group of herbivorous insects. They appear during the Carboniferous (Serpukhovian stage) and continue through to the Late Permian. This large and diverse group includes 50% of all known Paleozoic insects. Palaeodictyopteroidea nymphs possessed movable wing pads and appear to have been able to perform simple flapping flight.