In cockroach,the ootheca is produced by the secretion of:

Identify the location and function of the following structures in a cockroach:
$(i)$ Gizzard
$(ii)$ Hepatic caecum

Tracheae of cockroach and mammal are similar in having

The figure below shows the digestive system of a cockroach. What are $P$ and $Q$?

$A$: In cockroach,inspiration is a passive process.
$R$: Expansion of abdominal cavity allows the space for expansion of the tracheal trunk,as a result,air enters through the spiracle.

Identify $X, Y$ and $Z$ in the given figure of the male reproductive system of a cockroach.