Fairyflies have two to four larval stages, all apparently without functional spiracles or tracheae. The bubble covers at least some of the spiracles, permitting air to enter the tracheae. The instars are separable by examining the posterior spiracles, or openings to the breathing system. The posterior spiracles (on the anal segment) are usually on two cylindrical lobes. The main difference is that the Notostigmomorpha have their spiracles located mid-dorsally. The next four somites, 3 to 6, all bear pairs of spiracles. The anterior spiracles (prothoracic spiracles) end bluntly and are not elongated. Stingray spiracles are openings just behind its eyes. Air is taken in through openings on the sides of the abdomen called spiracles. The abdomen has ten segments, each with a pair of spiracles for respiration. The abdominal segments I through IV possess spiracles, which the wasp breathes through. Air enters the respiratory systems of insects through a series of external openings called spiracles. The black dot is the flea's exposed hind legs, respiratory spiracles and reproductive organs. Some small insects do demonstrate continuous respiration and may lack muscular control of the spiracles. Tadpoles have spiracles through which water exits the opercular chamber.