on the thorax, yet three pairs may be found on different rings in different groups, though not actually existing in one individual. The ideal number of pairs is three, or for the entire body eleven. which one is thoracic (on the prothorax), while the eight other pairs are abdominal.

Spiracle, in arthropods, the small external opening of a trachea (respiratory tube) or a book lung (breathing organ with thin folds of membrane resembling book leaves). Spiracles are usually found on certain thoracic and abdominal segments.

How is the third pair of legs adapted for jumping? what system do spiracles open into on a grasshopper? All segments in abdomen except last 2. None on thoraic segments.

Insects have spiracles on their exoskeletons to allow air to enter the trachea. In insects, the tracheal tubes primarily deliver oxygen directly into the insects’ tissues. The spiracles are located laterally along the thorax and abdomen of most insects—usually one pair of spiracles per body segment.

Examples of Spiracles Skates, cartilaginous fish that have a flat body and wing-like pectoral fins attached to their head, and stingrays sometimes use spiracles as their primary method of breathing, bringing oxygenated water into the gill chamber where it is exchanged for carbon dioxide.

Instead of nostrils, insects breathe through openings in the thorax and abdomen called spiracles. Insects that are diapausing or non-mobile have low metabolic rates and need to take in less oxygen. Insects exchange oxygen and carbon dioxide through spiracles (noted by circle).

Some insects can freeze solid, then thaw, and walk away just fine. They are also very good at surviving without oxygen. If humans don’t receive oxygen, they can die within a few minutes, but almost all insects can survive without oxygen for many hours.

As far as entomologists are concerned, insects do not have pain receptors the way vertebrates do. They don’t feel ‘pain,’ but may feel irritation and probably can sense if they are damaged.