Question

Which of the following characteristics is incorrect with respect to cockroach?

• A. 10th abdominal segment in both sexes, bears a pair of anal cerci
• B. A ring of gastric caeca is present at the junction of midgut and hindgut
• C. Hypopharynx lies within the cavity enclosed by the mouth parts
• D. In females, 7th-9th sterna together form a genital pouch

Answer 1

The correct option is B A ring of gastric caeca is present at the junction of midgut and hindgut

A pair of filamentous structures called anal cerci are present in both sexes in the 10th segment.

Hence the statement in option a is correct.

Hepatic caeca or gastric caeca is present at the junction of the foregut and midgut of the alimentary canal in the cockroach. They are a ring of 6-8 blind tubules that secrete digestive juices.

At the junction of midgut and hindgut, 100-150 yellow-coloured filamentous structures are present, called Malpighian tubules. They help in excretion.

Hence the statement in option b is incorrect.

Hypopharynx is a median flexible lobe present within the cavity enclosed by the mouth parts in the cockroach. It is also called tongue.

Hence the statement in option c is correct

The body of the cockroach is covered by a chitinous exoskeleton which is divided into plates called sclerites. The sclerites on the ventral side are called sterna. In the female cockroach, the 7th sternum is boat-shaped and together with the 8th and 9th sterna forms a brood or genital pouch. Fertilization is internal and occurs in the genital pouch.

Hence, the statement in option d is correct.