External genitalia in cockroach consist of small irregular chitinous plates known as

Options

A. Seminal vesicles
B. Collaterial gland
C. Phallomeres
D. Abdominal sclerites

Explanation

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks about the external genitalia of a cockroach and specifically what the small irregular chitinous plates are called.

2. **Understand the Structure**: The external genitalia of a cockroach is composed of several parts, including chitinous plates which are important for its reproductive system.

3. **Define the Chitinous Plates**: These plates are irregularly shaped and are made of chitin, a tough, protective substance found in the exoskeleton of arthropods.

4. **Name the Plates**: The specific name for these small irregular chitinous plates in the cockroach's external genitalia is "phallomere" or "gonapophysis."

5. **Conclusion**: Therefore, the external genitalia in cockroaches consist of small irregular chitinous plates known as phallomeres.

**Final Answer**: The external genitalia in cockroaches consist of small irregular chitinous plates known as phallomeres.

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