Fertilized eggs of Periplaneta americana are encased in

Options

A. Ootheca
B. Cocoon
C. Phallomere
D. Genital chamber '

Answer

### Step-by-Step Text Solution:

1. **Identify the Organism**: The question refers to the fertilized eggs of *Periplaneta americana*, which is commonly known as the American cockroach.

2. **Understand the Reproductive System**: In female cockroaches, the reproductive system consists of two large ovaries located laterally in the abdominal segments. Each ovary is made up of a group of ovarian tubules that produce eggs.

3. **Fertilization Process**: After fertilization, the eggs need protection as they develop.

4. **Encasement of Eggs**: The fertilized eggs of the cockroach are encased in a structure known as an ootheca. This is a protective casing that holds the eggs together.

5. **Production of Ootheca**: Female cockroaches can produce around 9 to 10 oothecae, with each ootheca containing approximately 14 to 16 fertilized eggs.

6. **Elimination of Incorrect Options**:
- **Cocoon**: This term is associated with organisms like earthworms, where fertilization occurs within the cocoon. Thus, it is not applicable to cockroaches.
- **Felomere**: This is not a term used for egg encasement in cockroaches.
- **Genital Chamber**: This is part of the reproductive system but does not serve as a protective casing for the eggs.

7. **Conclusion**: Based on the above information, the correct answer to the question is that fertilized eggs of *Periplaneta americana* are encased in an **ootheca**.