The beauty of nature..creation of The Creator..
* Flies are adapted for aerial movement, and typically have short and streamlined bodies. The first segment of the fly is the head and consists of ocelli, antennae,compound eyes, and the mouth (the labrium, mandible and maxilla make up the mouth). The second segment of the thorax, which bears the wings and contains the flight muscles, is greatly enlarged, with the other two segments being reduced to collar-like structures. The third segment bears the halteres, which help to balance the insect during flight. A further adaptation for flight is the reduction in number of the neural ganglia, and concentration of nerve tissue in the thorax, a feature that is most extreme in the highly derived Muscomorpha infraorder.-http://en.wikipedia.org/wiki/Flies