The figure given below shows the alimentary canal of cockroach with few structures labelled as $1,2,3$ and $4 .$ Identify the correct identification of the structure which is also called proventriculus and helps in grinding the food particles.
$1$
$2$
$3$
$4$
The terga, sterna and pleura of cockroach body are joined by
In cockroach
Choose incorrect answer about characters shown in cockroach.
Identify $X$ the from the figure.
It is part of male cockroach