Peritreme in cockroach is

Options

A. (a) tracheal network
B. (b) stigmatal opening
C. (c) one of the abdominal segments
D. (d) annular sclerite surrounding spiracle

Answer

### Step-by-Step Solution:

1. **Understanding Peritreme**:
- The peritreme in cockroaches is a component of their respiratory system. It is important to identify its role and structure.

2. **Composition**:
- The peritreme is formed from a material called sclerite, which is part of the exoskeleton of the cockroach. This exoskeleton is made of chitin.

3. **Structure**:
- The peritreme is described as a ring-like or annular structure. This means it encircles the spiracles, which are the openings on the body surface.

4. **Location**:
- The peritreme is present in both the thorax and abdomen of the cockroach, indicating its widespread presence in the body.

5. **Function**:
- The primary function of the peritreme is to support the spiracles. Spiracles are small openings that facilitate gas exchange, similar to how nostrils function in humans.

6. **Analyzing Options**:
- Option A (tracheal network): This is incorrect because the peritreme is not the tracheal network itself.
- Option B (stigmatal opening): This is also incorrect as the stigmata refer to the spiracles, not the peritreme.
- Option C (one of the abdominal segments): This is incorrect as the peritreme is not a segment but part of the integument.
- Option D (annular sclerite surrounding spiracles): This is correct as it accurately describes the peritreme's shape, composition, and function.

7. **Conclusion**:
- The correct answer is Option D: "annular sclerite surrounding spiracles."