The species is commonly known as the common fruit fly or vinegar fly, and is one of the most commonly used model organisms in biology, including studies in genetics, physiology and life history evolution. Flies belonging to the family Tephritidae are also called fruit flies, which can lead to confusion, especially in Australia where the term fruit fly refers to the Tephritidae, an economic pest in fruit production.

Wildtype fruit flies have brick red eyes, are yellow-brown in color, and have transverse black rings across their abdomen. They exhibit sexual dimorphism: females are about 2.5 millimeters (0.1 inches) long; males are slightly smaller and the back of their bodies is darker. Males are easily distinguished from females based on color differences, with a distinct black patch at the abdomen, less noticeable in recently emerged flies (see fig), and the sexcombs (a row of dark bristles on the tarsus of the first leg). Furthermore, males have a cluster of spiky hairs (claspers) surrounding the reproducing parts used to attach to the female during mating. There are extensive images at Fly Base.

Content Resource : http://en.wikipedia.org/wiki/Drosophila_melanogaster