Formation of Ootheca :
The ovipositors push the fertilized eggs into the oothecal chamber in 2 rows of 8 in each row. In the oothecal chamber. the secretions of the collateral glands form a dark brown colored covering around the fertilized eggs. The resulting structure is called as ootheca. The formation of ootheca takes about 20 hours.
The length of the ootheca is 8-10 mm. It’s one end is serrated. A female cockroach forms about 20-40 oothecae in it’s life span. The female carries the ootheca for few days & finally it deposit’s the ootheca in some dark, dry & warm place. The eggs of the cockroach are centrolecithal & are covered by chitinous shell. Every egg has a minute micropyle.
