Which of the following characteristics is incorrect with respect to cockroach?
- 10th abdominal segment in both sexes, bears a pair of anal cerci
- A ring of gastric caeca is present at the junction of midgut and hind gut
- Hypopharynx lies within the cavity enclosed by the mouth parts
- In females, 7th-9th sterna together form a genital pouch
Answer
(2) A ring of gastric caeca is present at the junction of midgut and hind gut
Solution
As per NCERT, in cockroach a ring of 6–8 blind tubules called hepatic or gastric caecae is present at the junction of foregut and midgut.
∵ At the junction of midgut and hindgut, another ring of 100–150 yellow coloured thin filamentous Malpighian tubules is present, not gastric caeca.
∴ Statement (2) is incorrect.
The other statements are correct: the 10th segment bears a pair of jointed filamentous anal cerci in both sexes; the hypopharynx (tongue) lies within the cavity enclosed by the mouth parts; in females the 7th sternum is boat shaped and, together with the 8th and 9th sterna, forms a brood or genital pouch.
Answer: (2)