spiracle's Usage Examples:

b, spiracle on prothorax; c, protruded head region; d, tail-end with functional spiracles; e, f, head region with mouth hooks protruded; g, hooks retracted; h, eggs.

The young insect resembles its parent in most points, but the head is disproportionately large; the anterior abdominal spiracles are on the second segment instead of on the first, and the foot has only a single segment.

The subsequent expansion of the body causes fresh air to enter the tracheal system, and if the spiracles be then closed and the body again contracted, this air is driven to the finest branches of the air-tubes, where a direct oxygenation of the tissues takes place.

- Water-scorpion (Nepa cinerea) with raptorial fore-legs, heteropterous wings, and long siphon for conveying air to spiracles.

These spiracles have firm chitinous edges, and can be closed by valves moved by special muscles.

of the abdominal pleura) which when pressed together form a tube whose point can pierce the surface film and convey air to the hindmost spiracles which are alone functional in the adult.

They breathe by piercing the surface film with the tail, where a pair of spiracles are situated.

After eating the contents of the egg, the larva moults and becomes a fleshy grub with short legs and with paired spiracles close to the dorsal region, so that, as it floats in and devours the honey, it obtains a supply of air.

30 a and spiracles, and, moulting, emerge from their old skin as nymphs.

The number of spiracles is greatly reduced; in the adult a pair is present on the mesothorax, sometimes also a pair on the metathorax, and there is always a pair on the first and another pair on the eighth abdominal segment.

Specially characteristic of the class, however, is the presence of a complex system of air-tubes (tracheae) for respiration, usually opening to the exterior by a series of paired spiracles on certain of the body segments.

Consequently when the insect dives, an air-bubble forms around it, a supply of oxygen is thus secured for breathing and the water is kept away from the spiracles.

Atmospheric air gains access to the air-tubes through paired spiracles or stigmata, which usually occur laterally on most of the body-segments.

Synonyms:

blowhole, orifice, porta, stigma, opening,

Antonyms:

natural object, finish, closing,