alternative definition added about 4 years ago by Istvan Miko
External opening in the body wall for a tracheal air tube, which forms part of the
respiratory system of an insect; in most chalcids at least three sets of spiracles are visible, the
mesothoracic spiracle, propodeal spiracle, and metasomal spiracle, as well as sometimes a
Reference: Gibson , G. A. P., J. D. Read , and R. Fairchild. 1998. Chalcid wasps (Chalcidoidea): illustrated glossary of positional and morphological terms ..
Cross reference: None provided.