The head carries two antennae, the mandibles and maxillae with mandibulary and maxillary palps, two compound eyes, and sometimes up to three simple eyes. It contains most of the senses, some of the brains and the mouth of an insect.
The thorax consist of three segments, called prothorax, mesothorax, metathorax. The thorax is concerned with movement. Every segment carries a pair of legs, total six. It also carries the isenct's wings, if present. Usually 4, but 2 in the diptera and strepsiptera.
The abdomen is concerned with digestion, excretion and reproduction. It contains the heart, testes or ovary, the stomach, the excretion organs, the sex organs, energy storage reserves, and the stinger, if present.