Classification of tracheal system based on number and arrangement of functional spiracles

I. Holopneustic:

• 2 pairs of spiracles on thorax and 8 pairs on abdomen. All the spiracles are functional.
• Eg. dragonflies, grasshoppers and cockroach.

II. Hemipneustic:

• One or more pairs of spiracles become non-functional. It is divided into following:

a) Peripneustic: Metathoracic spiracle is closed. 1 + 0 + 8. e.g.: larvae of Lepidoptera, Hymenoptera, Coleoptera.

b) Amphipneustic: Only mesothoracic and last pair of abdominal spiracles are open. 1+0+1. e.g: larva of cyclorrhaphan Diptera.]

c) Propneustic: Only one pair i.e. mesothoracic spiracles are open, 1 + 0 +0 e.g.: mosquito pupa

d) Metapneustic: Only last pair of abdominal spiracles are open. 0 + 0 + 1. e.g.: mosquito larvae

e) Apneustic: No functional spiracles. e.g: mayfly larva, nymph of Odonata.

III. Hypopneustic:

• 1 or 2 pairs of spiracles may completely disappear or absent e.g.: Siphunculata, Mallophaga

IV. Hyperpneustic:

• More than 10 pairs of spiracles are present e.g:Japyx sps. (dipluran)