Question

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

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

Answer 1

The Correct Option is A

To solve this question, we need to critically analyze each of the given characteristics with respect to the anatomy of a cockroach and identify the incorrect one.

1. Option A: "A ring of gastric caeca is present at the junction of midgut and hind gut."

   This statement is incorrect. In cockroaches, a ring of gastric caeca is present at the junction of the foregut and midgut. Thus, the gastric caeca serve to increase the surface area for digestion and play a role in the initial digestion of food. They are not located at the junction of the midgut and hindgut, making this option the correct answer to the question posed.

2. Option B: "Hypopharynx lies within the cavity enclosed by the mouth parts."

   This statement is correct. The hypopharynx is a part of the mouthparts of a cockroach, located between the maxillae, and acts like a tongue, involved in manipulating food.

3. Option C: "In females, $7^{th}-9^{th}$ sterna together form a genital pouch."

   This statement is accurate. In female cockroaches, the 7th to 9th abdominal segments are modified to form a brood chamber, also known as a genital pouch, which serves to carry the developing eggs.

4. Option D: "$10^{th}$ abdominal segment in both sexes, bears a pair of anal cerci."

   This statement is correct. Both male and female cockroaches indeed have a pair of anal cerci on the 10th abdominal segment, which are sensory organs used to detect movement in the environment.

Given the explanations and elimination process, the statement in Option A is identified as incorrect since it provides a factually inaccurate description of the digestive anatomy of cockroaches.