Insects have evolved many variations of wings adapted for different purposes. Wing venation, or the pattern of veins in wings, is an important taxonomic feature used to identify insect groups. The archedictyon is a hypothetical model of the earliest wing venation pattern containing 6-8 longitudinal veins. Wing morphology varies across orders, with dragonflies having membranous wings, flies developing halteres for flight stabilization, and beetles possessing hardened elytra over their hind wings.

1. EXTERNAL & INTERNAL MORPHOLOGY:WINGS
Insects have evolved many variations of the wing. Wing venation is a commonly used
taxonomic character, especially at the family and species level.
Membranous wings are thin and more or less transparent. This type of wings is found
among the Odonata and Neuroptera.
Wing venation
The archedictyon is the name given to a hypothetical scheme of wing venation
proposed for the very first winged insect. It is based on a combination of speculation
and fossil data. Since all winged insects are believed to have evolved from a common
ancestor, the archediction represents the "template" that has been modified (and
streamlined) by natural selection for 200 million years. According to current dogma, the
archedictyon contained 6-8 longitudinal veins. These veins (and their branches) are
named according to a system devised by John Comstock and George Needham -- the
Comstock-Needham System:
 Costa (C) – the leading edge of the wing
 Subcosta (Sc) – second longitudinal vein (behind the costa), typically
unbranched
 Radius (R) – third longitudinal vein, one to five branches reach the wing
margin
 Media (M) – fourth longitudinal vein, one to four branches reach the wing
margin
 Cubitus (Cu) – fifth longitudinal vein, one to three branches reach the wing
margin
 Anal veins (A1, A2, A3) – unbranched veins behind the cubitus

2. DRAGONFLY
Veins in the wing provide support for the thin, delicate membranous cuticle that
forms the wing itself. Many of the veins have tracheae (tubes that function in
respiration) and provide a passage for haemolymph which is essential for the
functioning of the numerous sense organs found on the wings, including wind
sensitive hairs. Wing venation is also an important morphological characteristic in
taxonomy and can be used to identify many insect groups. Compare the dragonfly
wings to the wings of fruitfly below..

3. Diptera : Halteres are an extreme modification among the order Diptera (true flies), in
which the hind wings are reduced to mere nubs used for balance and direction during
flight.
In a normal adult fly, the second thoracic segment features a pair of wings, while the
third thoracic segment has a pair of small, balloon-shaped structures called halteres
(see arrow in inset). A modified second wing, the haltere serves as a flight stabilizer.

4. MOSQUITO WINGS
Elytra (sing. elytron) are the hardened, heavily sclerotized forewings of beetles (Order
Coleoptera) and are modified to protect the hind wings when at rest.
A variation of the elytra is the hemelytra. The forewings of Hemipterans are said to be
hemelytrous because they are hardened throughout the proximal two-thirds
(approximately), while the distal portion is membranous. Unlike elytra, hemelytra
function primarily as flight wings. In both cases, the membranous hind wings (when
present) are used in flight and are folded beneath the forewings when at rest.

5. Frenulum
The frenulum is a row of bristles along the leading (front) edge of the hind wing of
butterflies and moths and also in some Hymenoptera such as bees and wasps. The
frenulum connects the hind wing and fore wing and makes the two wings act a single
surface during flight. It is therefore more efficient.
The wings of butterflies and moths are covered with scales, and mosquitoes possess scales along
wing veins.

6. Tegmina (singular Tegmen) is the thickened fore wings of some insects. The tegmina
are used to protect the more vulnerable hind wings. The tegmina offer little or no power
during flight and are often held out of the way of the hind wings.
Insects possessing tegmina include:
 Earwigs
 Grasshoppers and Crickets
 Cockroaches
 Mantids