elytrum

/ˈɛlɪtrəm/
noun
  1. The hardened forewing of a beetle or similar insect, which forms a protective case for the hindwing.
    • The collector carefully pinned the beetle, making sure not to damage its elytrum.
    • The beetle's elytrum was shiny and green, protecting its delicate flying wings underneath.
    • When the ladybug landed, its elytrum opened to reveal transparent wings.