KoXEOS, a sheath, and 7rTEpa, wings) was first used by Aristotle, who noticed the firm protective sheaths, serving as coverings for the hind-wings which alone are used for flight, without recognizing their correspondence with the fore-wings of other insects.
The identification of the elytra of beetles with the fore-wings of other insects has indeed been questioned (1880) by F.
Tower (1903), of nervures similar to those of the hind-wing, and by the proof that the small membranous structures present beneath the elytra of certain beetles, believed by Meinert to represent the whole of the true fore-wings, are in reality only the alulae.
The hard fore-wings (elytra) are strengthened with marginal ridges, usually inflected ventrally to form epipleura which fit accurately along the edges of the abdomen.
3, t - on the mesothorax at the base of the fore-wings.