Spiracle (lower center; opening that lets oxygen into the tracheal system) and haltere (upper right; orange knob-shaped organ that helps balance the insect in flight) on the thorax of Tabanus nigrovittatus (Diptera: Tabanidae). Dark brown horizontal structures at top are the wings.

Spiracle (lower center; opening that lets oxygen into the tracheal system) and haltere (upper right; orange knob-shaped organ that helps balance the insect in flight) on the thorax of Tabanus nigrovittatus (Diptera: Tabanidae). Dark brown horizontal structures at top are the wings.