The housefly is a small hairy insect. It is divided into the head, thorax and abdomen.

The head bears a pair of very short hairy antennae, 2 large compound eyes, 3 simple eyes (ocelli)and a mouth part which is a tubular structure called proboscis

The thorax, like the rest of the body is covered with hair. It is grey in colour with black stripes on the dorsal side. 3 pairs of hairy jointed legs are attached to the thorax. Each of the legs ends with 2 small sticky pads with a pair of sharp claws. The pad makes it possible for the housefly to walk on ceilings. The thorax also bears a pair of transparent wings and another pair which are merely tiny stumps called balancers or halteres  

The abdomen is light in colour and contains segments, which stop at the posterior end, but only 4 segments can be seen. The abdomen possesses spiracles on each side of the segments, which allows air to enter and leave the body of the housefly during breathing.

Diagram of housefly