Final answer:
The three thoracic segments of an insect are the prothorax, mesothorax, and metathorax, each bearing a pair of legs and, in some cases, wings.
Step-by-step explanation:
The three segments of an insect's thorax, from front to back, are:
- Prothorax
- Mesothorax
- Metathorax
Each of these segments is distinct and performs different functions. The prothorax is the segment closest to the head and it bears the first pair of legs. The mesothorax is the middle segment, which usually bears the second pair of legs and the front wings if the insect has wings. Finally, the metathorax is the third segment, bearing the hind wings and the third pair of legs. These segments are part of the segmented body plan that characterizes the phylum Arthropoda, which also includes a chitinized exoskeleton and jointed appendages, and are particularly distinct within the subphylum Hexapods to which all insects belong.