fly-case

from The Century Dictionary.

• noun The case or covering of an insect; specifically, the anterior wings of beetles, so hardened as to cover the whole upper part of the body, concealing the second pair of wings; the elytra. See cut under Coleoptera.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) The covering of an insect, esp. the elytra of beetles.