Question

Draw a well labelled diagram showing the alimentary canal of cockroach and label any 4 parts. What is meant by paurometabolous development in cockroaches?

Answer 1

Hint: Cockroaches are black or brown bodied animals. There any entry Canal present in the body cavity is divided into foregut, midgut and hindgut (three main reasons).

Complete answer
Mouth of cockroaches open into the pharynx leads to a narrow passage called Oesophagus. Then the oesophagus opens into a sac-like structure called crop, that is basically used for shortage of food.
After the crop there is a part called a gizzard which helps in grinding of food.
The foregut of cockroaches is lined with cuticles. Then there is a portion called hepatic caeca which is present at the junction of foregut and midgut. This hepatic caeca contains 6-8 ring-like blind tubules which secrete digestive juices.
Then there are Malpighian tubules present at the junction of midgut and hindgut which are filamentous and yellow in colour. This yellow colourmelpighiin tubule helps in removal of excretory products.
Then last Hindgut which mainly consists of ileum colour and rectum and hindgut is broader than midgut. Finally rectum opens into anus.

Paurometabolous Development in Cockroaches

>Development of cockroaches lacks Pupa Stage, So this is due to it being called incomplete metamorphosis or paurometabolous.
>Development only includes three stages like egg, nymph and adult.

Note:Many species of cockroaches are wild and are of no economic importance. Cockroaches can transmit a variety of bacterial diseases by contaminated food material.