Question

Spiracles found in cockroach are:

• A. 2 pairs in thorax and 100 pairs in abdomen
• B. 2 pairs in thorax and 6 pairs in abdomen
• C. 2 pairs in thorax and 8 pairs in abdomen
• D. 2 pairs in thorax and 4 pairs in abdomen

Answer 1

Answer: (C)

Spiracles or stigmata are special valve containing tubules through which atmospheric air enters and escapes out during gaseous exchange in cockroach. Spiracles are $20$ in number, out of these $2$ pairs are found in thoracic portion while rest $8$ pairs are found in abdominal portion. Thoracic spiracles are somehow larger than abdominal spiracles. Peritreme, a ring like sclerite surrounds each spiracle.