Which of the following statement is incorrect about development of periplaneta americana?

Options

A. On an average female produces 9-10 oothecae each containing 14-16 eggs
B. The development is paurometabolous
C. The nymph grows by moulting about 7-8 times to reach adult form
D. The next to last nymphal stage has wing pads but only adult cockroach has wings

Explanation

To determine which statement is incorrect about the development of Periplaneta americana (the American cockroach), we can analyze each statement provided:

1. **Statement 1**: "On average, the female produces 9 to 10 oothecae, each containing 14 to 16 eggs."
- **Analysis**: This statement is correct. Female cockroaches do produce multiple oothecae, and each ootheca typically contains a number of eggs within the range mentioned.

2. **Statement 2**: "The development is hemimetabolous."
- **Analysis**: This statement is also correct. The development of Periplaneta americana is indeed hemimetabolous, which means it undergoes incomplete metamorphosis, transitioning from nymph to adult without a pupal stage.

3. **Statement 3**: "Nymphs grow by molting about 7 to 8 times to reach adult form."
- **Analysis**: This statement is incorrect. Nymphs of Periplaneta americana actually molt approximately 13 times before they reach the adult form. Therefore, this statement does not accurately reflect the developmental process.

4. **Statement 4**: "The next to last nymphal stage has wing pads, but only the adult cockroach has wings."
- **Analysis**: This statement is correct. In the development of cockroaches, the nymphs do develop wing pads, but only the fully mature adult cockroach has fully developed wings.

Based on the analysis, the incorrect statement about the development of Periplaneta americana is:

**Answer**: "Nymphs grow by molting about 7 to 8 times to reach adult form."

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