Metanotum

Definition

The dorsal (upper) sclerite of the metathorax, the third and posterior segment of the insect thorax. In most insects, the metanotum is reduced relative to the mesonotum and bears the hindwings when present; in wingless groups or reduced-wing forms (e.g., many beetles, parasitic wasps), it may be small or modified. In Hymenoptera Apocrita, the metanotum is often partly concealed where the first abdominal segment (propodeum) fuses to the metathorax.

Etymology

From Greek meta- (after, behind) + noton (back)

Example

In dragonflies (Odonata), the metanotum is well-developed and conspicuous, bearing large hindwings; in worker ants (Formicidae), the metanotum is reduced and overgrown by the propodeum, forming a narrow waist segment.

Related Terms

• Metathorax
• Mesonotum
• pronotum
• propodeum
• metapleuron
• metasternum
• scutellum
• Haltere

Usage Notes

Distinguished from mesonotum (middle thoracic dorsum) and pronotum (first thoracic dorsum). The relative size and shape of the metanotum are taxonomically informative: enlarged in many Heteroptera (true bugs), reduced or hidden in Apocrita, and bearing specialized glands or structures in some groups. Do not confuse with metanotum as a specific epithet in species names (e.g., some Braconidae).