Describe the digestive tract or alimentary canal of a cockroach with a diagram.

(N/A) The alimentary canal of a cockroach is complex and is divided into three regions: Foregut,Midgut,and Hindgut.
$1$. Foregut: The mouth opens into a short tubular pharynx,which leads to a narrow tubular passage called the oesophagus. This opens into a sac-like structure called the crop,used for storing food. The crop is followed by the gizzard or proventriculus. It has an outer layer of thick circular muscles and a thick inner cuticle forming six highly chitinous plates called teeth,which help in grinding food particles. The entire foregut is lined with a cuticle.
$2$. Midgut: The gizzard opens into the midgut. At the junction of the foregut and midgut,a ring of $6-8$ blind tubules called hepatic or gastric caecae is present,which secretes digestive juices.
$3$. Hindgut: The midgut opens into the hindgut. At the junction of the midgut and hindgut,another ring of $100-150$ yellow-coloured,thin,filamentous Malpighian tubules is present. They help in the removal of excretory products from the haemolymph. The hindgut is broader than the midgut and is differentiated into the ileum,colon,and rectum. The rectum opens out through the anus.