Thorax
Insects have three body parts, Head, Thorax and Abdomen. I therefore believe Thorax is the correct answer to your question.
I am pretty sure that the answer is thorax. the insect has three parts in it. they are the head, thorax, and abdomen. the head of course is on the top. the thorax is the middle part. the abdomen is at the end. i usually think of ants when i think of this.
the thorax
Its exoskeleton.
the tympanum
their eyes
Abdomen
It is the tongue.
The heart is a common part of the body that is found in snakes and insects. Eyes are another common feature between insects and snakes.
The body part that insects have and cat fleas do not is wings. Fleas are wingless insects that feed on the blood of animals including cats.
If you are talking insects the middle part is the abdomen. The head is at the top and the thorax is the back end.
the nervous system