Spiracles

The adult honeybee has three thoracic and seven abdominal spiracles on each side, because the first abdominal segment, the prono-tum, has joined the thorax. All the spiracles except the smaller second are capable of controlled closing and opening. Spiracles posses a muscular apparatus controlled by the nervous system that closes to prevent escape of air in the tracheal tree or to adjust the flows of air through the spiracles. Most insects have ten spiracles on each side, two on the thorax and eight on each side of the abdomen. The first and largest spiracles lie between the pro and meso thorax, each partially hidden by the overlapping edges of the pronotum. The second spiracle is small lying between the upper angles of the plates of the meso and meta thorax. The third spiracle, fully exposed, is on the side of the pronotum. The next six are in the lower portions of the first six tergal plates of the abdomen, and the last spiracle is at the base of the sting.

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