The egg-shell ultrastructure of Blatticola blattae has been studied under scanning and transmission electron microscopy. Similar to other studied oxyurids, it consists of five layers: a lipid layer, a chitinous layer, a vitelline layer, internal and external uterine layers. Unlike in the closely related thelastomatid Hammerschmidtiella diesingi, the external uterine layer of B. blattae has a honeycomb structure, the complex system of tightly joined prismatic chambers.