select the incorrect statement about the reproductive system of male cockroach.

Options

A. Vasa deferentia - Open into the ejaculatory duct via seminal vesicle.
B. Seminal vesicles - 1 pair
C. Mushroom gland - It opens in phallic gland .
D. Ejaculatory duct - Both seminal vesicles form a single ejaculatory duct.

Answer

To solve the question regarding the incorrect statement about the reproductive system of the male cockroach, we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding the Reproductive System of Male Cockroach**:
- The male cockroach has a complex reproductive system that includes various structures like seminal vesicles, ejaculatory duct, and glands.

2. **Analyzing the Options**:
- **Option A**: "Wasa differentiate open into ejaculatory duct via seminal vesicle."
- This statement is correct. The vas deferens (wasa) does open into the ejaculatory duct via the seminal vesicle.

- **Option B**: "Seminal vesicle one pair."
- This statement is also correct. Male cockroaches have one pair of seminal vesicles.

- **Option C**: "Mushroom gland opens in phallic gland."
- This statement is incorrect. The mushroom gland does not open into the phallic gland; instead, the phallic gland opens near the gonopore.

- **Option D**: "Ejaculatory duct both seminal vesicles form a single ejaculatory duct."
- This statement is correct. The two seminal vesicles do converge to form a single ejaculatory duct.

3. **Identifying the Incorrect Statement**:
- From the analysis, the incorrect statement is **Option C**: "Mushroom gland opens in phallic gland."

### Final Answer:
The incorrect statement about the reproductive system of the male cockroach is: **"Mushroom gland opens in phallic gland."**

---