Tracheal System of a Hover Fly Larva

diagram of the tracheal system of a hover fly

Air enters the tracheal system through the valve-like spiracles that are located laterally along the thorax and abdomen. There are two spiracles per segment, though not all segments bear spiracles.

The air then passes into a lateral longitudinal tracheal trunk, eventually diffusing through the network of tracheal tubes and into the tracheoles. The oxygen diffuses across the moist membrane of the tracheole and into the connecting cell. At the same time carbon dioxide (a waste product of cellular respiration) diffuses out of the cell, into the tracheole and travels out of the body via the tracheal system.