Which of the following statement is incorrect with respect to sericulture -

Options

A. Silk glands are modified salivary gland of caterpillar larva.
B. `5^(th)` instar forms cocoon.
C. Silk consists of sericin and fibrinogen protein.
D. Reeling is the process of removal of fibre from killed cocoon

Answer

**Step-by-Step Solution:**

1. **Understand the Concept of Sericulture:**
- Sericulture is the practice of breeding silkworms for the production of silk. The primary species involved in this process is *Bombyx mori*.

2. **Identify Key Components of Sericulture:**
- Silkworms produce silk through modified salivary glands, which secrete a protein that forms silk threads.
- The silk is produced in the form of cocoons, which are made up of two main proteins: fibroin and sericin.

3. **Analyze the Statements Provided:**
- The question requires us to identify which statement about sericulture is incorrect.
- The statements likely include information about the silk glands, the composition of silk, and the process of reeling silk from cocoons.

4. **Evaluate Each Statement:**
- **Statement 1:** Refers to silk glands as modified salivary glands. This is correct.
- **Statement 2:** Discusses the composition of silk, mentioning fibroin and sericin. This is also correct.
- **Statement 3:** Mentions "instaform cocoon" and incorrectly states that it contains "fibrenogen" instead of "fibroin." This is incorrect.
- **Statement 4:** Describes the process of reeling silk from cocoons, which is accurate.

5. **Conclusion:**
- The incorrect statement regarding sericulture is the one that mentions "fibrenogen" instead of "fibroin." Therefore, option number 3 is the incorrect statement.