An ootheca (pl. oothecae) is a type of egg mass made by any member of a variety of species (usually insects or mollusks).
The word is a combination of oo-, meaning "egg", from the Greek word oion, and theca, meaning a "cover" or "container", from the Greek theke.
An ootheca usually contains many eggs surrounded by a foam of protein which may then harden into a tough casing for protection. Notable ootheca-making insects are the mantid and cockroach.