You searched for: “thecae
theca (s), thecae (pl)
1. A case, covering, receptacle, or sheath; such as, the pollen sac of an anther, the spore case of a moss, or the outer covering of the pupa of certain insects.
2. The outer covering of the cocoon of certain insects.
(Greek > Latin: case, capsule, sheath, container, receptacle [also: a placing, a setting, a putting]; "a place where" something is kept)