Archedictyon is a name given to a hypothetical

Hypothesis

A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...

 scheme of wing

Wing

A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...

 venation

Vein

In the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...

 proposed for the common ancestor of all winged insects

Insect flight

Insects are the only group of invertebrates known to have evolved flight. Insects possess some remarkable flight characteristics and abilities, still far superior to attempts by humans to replicate their capabilities. Even our understanding of the aerodynamics of flexible, flapping wings and how...

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Description

The nature of the archedictyon is an important consideration in the taxonomic classification

Taxonomy

Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 of the large, primitive Palaeozoic insects known as Palaeodictyoptera

Palaeodictyoptera

The Palaeodictyoptera are an extinct order of medium-sized to very large, primitive Palaeozoic paleopterous insects.-Overview:They were characterised by beak-like mouthparts, similarity between fore- and hind wings, and an additional pair of winglets on the prothorax, in front of the first pair of...

 and was used by Adolphe-Théodore Brongniart for this purpose as early as 1854. A National Museum of Natural History

National Museum of Natural History

The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. Admission is free and the museum is open 364 days a year....

 database

Database

A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

 for the study of ant

Ant

Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

s, wasp

Wasp

The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...

s, bee

Bee

Bees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...

s and termite

Termite

Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...

s describes the archedictyon as:

...the primitive original vein network characterizing the wings of many of the most ancient insect fossils (T-B, after Needham; Mackerras, in CSIRO

Commonwealth Scientific and Industrial Research Organisation

The Commonwealth Scientific and Industrial Research Organisation is the national government body for scientific research in Australia...

); in Mastotermitidae and Hodotermitidae (Isoptera), the complex network or reticulum

Reticulum

Reticulum is a small, faint constellation in the southern sky. Its name is Latin for a small net, or reticle—a net of crosshairs at the focus of a telescope eyepiece that is used to measure star positions...

 of irregular veinlets between the veins in the apical

Apical

Apical, from the Latin apex meaning to be at the apex or tip, may refer to:*Apical , an anatomical term of location for features associated with the base of an organism or structure...

 3 quarters of both wings, including the anal lobe (Emerson).

According to a 1999 scientific paper

Academic publishing

Academic publishing describes the subfield of publishing which distributes academic research and scholarship. Most academic work is published in journal article, book or thesis form. The part of academic written output that is not formally published but merely printed up or posted is often called...

 about the evolution of flght in Palaeozoic Palaeoptera, although the archedictyon of some Palaeodictyoptera have long been believed to be generalized plesiomorphic reticulation from which true cross veins developed through evolution

Evolution

Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

, these may actually be an adaptive feature.

Structure

The archedictyon is believed to have contained between six and eight longitudinal veins, but current understanding of the design is based on a combination of fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 data

Data

The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...

 and speculation.

The "Comstock-Needham system" designed by entomologists

Entomology

Entomology is the scientific study of insects, a branch of arthropodology...

 John Henry Comstock

John Henry Comstock

John Henry Comstock was an eminent researcher in entomology and arachnology and a leading educator. His work provided the basis for classification of butterflies, moths, and scale insects.-Early life and education:...

 and George Needham describes these veins and their branches:

• Costa(C): the leading edge of the wing
• Subcosta(Sc): the second longitudinal vein (behind the costa), typically unbranched
• Radius R): the third longitudinal vein, one to five branches reach the wing margin
• Media(M): the 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): the unbranched veins behind the cubitus

Crossveins are named based on their relative position to the more prominent longitudinal veins:

• C-SC crossveins run between the costa and subcosta
• R crossveins run between adjacent branches of the radius
• R-M crossveins run between the radius and media
• M-CU crossveins run between the media and cubitus

Extant species

The hypothetical primitive wing venation pattern is often used as a basis for describing the pattern in modern insects.

In extant insects, the term implies a retention of primitive characteristics but not necessarily a simplicity of design in comparison to the veinous network of other modern insect wings. Contemporary insects with wings to which the term archedictyon has been applied include the termite Mastotermes darwiniensis from Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 (illustration) and the praying mantis Orthodera novaezealandiae

Orthodera novaezealandiae

Orthodera novaezealandiae, known as the New Zealand Mantis or the New Zealand Praying Mantis, is a species of praying mantis which is, as both the scientific name and common names suggest, indigenous and endemic to New Zealand.-Description:...

from New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

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The term is also used in the discussion of phasmid

Phasmid

Phasmid may refer to:* Phasmid , a sensory structure in nematodes* Phasmatodea, the insect group which contains stick insects and walking-sticks* Phagemid, a vector used in gene cloning...

s and in such case refers to:

A network of non-directional veins in the costal region of the wing or in the elytron

Elytron

An elytron is a modified, hardened forewing of certain insect orders, notably beetles and a few of the true bugs ; in most true bugs, the forewings are instead called hemelytra, as only the basal half is thickened while the apex is membranous...

. It is these veins which make the elytron and costal region of the hindwing thicker and stiffer than the anal region of the hindwing.