In this insect diagram, the thorax is labelled B
The thorax is a part of an animal's body that is between the head and the abdomen.
In mammals, the parts that make up the thorax are the sternum, the thoracic vertebrae and the ribs. It starts from the neck and stop at the diaphragm.
In insects and crustaceans, it is the middle of the three main body sections. The walking legs are usually on the thorax.