Archedictyon

Archedictyon (from Greek Arche meaning first, original, ancient, primitive, or most basic and dictyo- meaning net or netlike, plural "archedictya") is a name given to a hypothetical scheme of wing venation proposed for the common ancestor of all winged insects.

The nature of the archedictyon is an important consideration in the taxonomic classification of the large, primitive Palaeozoic insects known as Palaeodictyoptera and was used by Adolphe-Théodore Brongniart for this purpose as early as 1854. A National Museum of Natural History database for the study of ants, wasps, bees and termites 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); in Mastotermitidae and Hodotermitidae (Isoptera), the complex network or of irregular veinlets between the veins in the apical 3 quarters of both wings, including the anal lobe (Emerson).

According to a 1999 scientific paper about the evolution of flight in Palaeozoic Palaeoptera, although the archedictyon of some Palaeodictyoptera have long been believed to be generalized plesiomorphic from which true cross veins developed through evolution, these may actually be an adaptive feature.

...
Wikipedia