Which of the following statements is correct about cockroach ?

Options

A. In females, the `6^(th)` sternum is boat- shaped and together with the `7^(th)` and `8^(th)` sterna form a brood or genital pouch
B. In males, the genital pouch is bounded dorsally by `9^(th)` and `10^(th)` sterna and ventrally by the `9^(th)` tergum
C. Females bear a pair of short, threadlike anal styles which are absent in males
D. The `10^(th)` segment has a pair of filamentous structures called anal cerci

Answer

To determine which statement is correct about the cockroach, let's analyze each option provided in the question step by step.

### Step 1: Analyze the First Statement
**Statement:** In females, the 6th sternum is boat-shaped and together with the 7th and 8th sternum forms a brood or genital pouch.

**Analysis:**
- The correct information is that the 7th sternum is boat-shaped, not the 6th. The genital pouch in females is indeed formed by the 7th, 8th, and 9th sternum. Therefore, this statement is **incorrect**.

### Step 2: Analyze the Second Statement
**Statement:** In males, the genital pouch is bounded dorsally by the 9th and 10th sternum and ventrally by the 9th tergum.

**Analysis:**
- In males, the genital pouch is bounded dorsally by the 9th and 10th sternum, but ventrally it is bounded by the 9th sternum, not the tergum. Thus, this statement is also **incorrect**.

### Step 3: Analyze the Third Statement
**Statement:** In females, a pair of short thread-like anal styles are present which are absent in males.

**Analysis:**
- This statement is incorrect because anal styles are actually found only in males, not in females. Therefore, this statement is **incorrect**.

### Step 4: Analyze the Fourth Statement
**Statement:** The 10th segment has a pair of filamentous structures called anal saccae.

**Analysis:**
- This statement is correct. Anal saccae are indeed present in both male and female cockroaches and serve as sensory structures. Thus, this statement is **correct**.

### Conclusion
Based on the analysis, the correct statement about cockroaches is the fourth one: "The 10th segment has a pair of filamentous structures called anal saccae."

### Final Answer
The correct statement about cockroach is: **The 10th segment has a pair of filamentous structures called anal saccae.**

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