The salivary glands in a cockroach open into the ..........

The figure given below shows the alimentary canal of a cockroach with a few structures labelled as $1, 2, 3$ and $4$. Identify the structure which is also called proventriculus and helps in grinding the food particles.

Which is a characteristic of a cockroach?

Answer in one word or one line. Where do you find Malpighian tubules?

Identify the location of hepatic or gastric caeca in a cockroach.

Haemolymph is the term used for the blood of the organism having