Metamerism: the arrangement in metameres.

Metameros: in Lepidoptera. the 6th to 8th abdominal segments.

Metamorphosis: is that series of changes through which an insect passes in its growth from egg through larva and pupa to adult: it is complete when the pupa is inactive and does not feed; incomplete when there is no pupa or when the pupa is active and feeds.

Metamorphosis dimidio: an incomplete transformation.

Metamorphosis perfecta: a complete transformation.

Metanotum: the primitively upper surface of the third or posterior thoracic ring: in Diptera, the oval arched portion behind, beneath the scutellum best developed in flies with long, slender abdomen: e.g. Tipulidae.

Metaphragma: the hindmost internal thoracic septum.

Metapleura: in Diptera, a swollen space at the outside of the metanotum, between it, the pteropleura and the hypopleura; in Hymenoptera, the piece behind and below the insertion of the hind wings.

Metapleural bristles: in Diptera, are inserted in the metapleura.

Metapneustic: larva, chiefly dipterous, in which the spiracles are confined to the posterior segment.