Sternellum: the second sclerite of the ventral part of each thoracic segment frequently divided into longitudinal parts which may be widely separated.
Sternite: the ventral piece in a ring or segment.
Sternopleura: in Diptera, the lower part of the pleura, below the sternopleural suture and above the front coxa.
Sternopleural bristles: in Diptera, are situated on the sternopleura below the sternopleural suture.
Sternopleural suture: in Diptera, is below and nearly parallel with dorso-pleural suture, separating the mesopleura from the sternopleura.
Sterno-rhabdite: a sternal rhabdite.
Sternorhynchi: that series of Homoptera in which the beak or rostrum apparently arises from the sternum between the anterior coxae; e.g. plant lice, etc.
Sternum -a: the breast: the middle portion of the under surface of thorax, between the coxal cavities.
Stethidium: the trunk: the entire thorax with all its appendages.
Stigma: a spiracle or breathing pore: a dense, often discolored portion of the costal margin of a wing, usually at the end of the radius; see anastomosis: in Diptera, a colored wing spot near the tip of the auxiliary vein: in Lepidoptera, the specialized patch of black scales on the primaries of Hesperidae.