2. THE THORAX
• The second (middle) tagma of an insect's body is called the thorax
• Adapted for locomotion
• Contains three pairs of walking legs and two pairs of wings.
• Composed of three body segments:
1. Prothorax
2. Mesothorax
3. Metathorax
4. • These segments are joined together rigidly to form a "box" that houses the musculature for the legs and
wings.
• Each segment has a dorsal sclerite, the notum (pronotum, mesonotum, and metanotum) which may be
further subdivided into an anterior scutum and a posterior scutellum.
• The ventral sclerite of each segment is the sternum (prosternum, mesosternum, and metasternum).
5. • The side of each segment is called the pleuron
•
• Pleuron is usually divided by a pleural suture into at least two sclerites
7. THE ABDOMEN
• Abdomen is the third functional region of body
• Located just behind the thorax.
8. • Each segment of the abdomen consists of a dorsal sclerite, the tergum.
• A ventral sclerite, the sternum.
• Joined to one another laterally by a pleural membrane.
9. • In many adult insects, there is a spiracle(opening to the respiratory system) near the pleural
membrane on each side of the first eight abdominal segments.
• At the very back of the abdomen, the anus is nestled between three protective sclerites:
• A dorsal epiproct and
• A pair of lateral paraprocts.
• A pair of sensory organs, the cerci
• These structures are tactile (touch) receptors. They are usually regarded as a "primitive" trait
because they are absent in the hemipteroid and holometabolous orders.
