Elytra

Definition

The hardened, shell-like forewings of beetles (order Coleoptera) and earwigs (order Dermaptera), modified from the ancestral flight-wing condition to serve as protective covers for the folded hindwings and abdomen. Elytra are typically thick, sclerotized, and often sculptured with pits, grooves, or color patterns; they meet in a straight line down the dorsal midline when closed and are lifted but not flapped during flight. In Coleoptera, the elytra are a primary diagnostic character; in Dermaptera, they are reduced and non-functional. The term is occasionally applied to fully thickened forewings in some true bugs (Hemiptera), though these are properly termed hemelytra when only partly hardened.

Etymology

From Greek elytron, meaning 'sheath' or 'covering'

Example

A lady beetle (Coccinellidae) at rest appears dome-shaped because its red-and-black spotted elytra completely conceal the membranous hindwings folded beneath; only when launching into flight does it raise the elytra to expose and deploy the functional flight wings.

Synonyms

• elytron (singular)
• shard (archaic)

Related Terms

• hemelytron
• tegmen
• Coleoptera
• Dermaptera
• Sclerite
• hindwing
• pterothorax

Usage Notes

The singular form elytron is rarely used in field speech; specialists typically refer to 'the elytra' even when discussing one wing. Contrast with hemelytra in true bugs, where only the basal portion is hardened, and with tegmina in grasshoppers and cockroaches, which are leathery but not fully sclerotized. The term should not be applied to the forewings of Orthoptera or Mantodea, which are properly tegmina. Some earwigs possess abbreviated elytra that do not cover the abdomen, a secondary reduction distinct from the beetle condition.