Drosophila is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit.

What is the meaning of melanogaster?

: a genus of hard-skinned puffballs of the family Sclerodermataceae — see red truffle.

Why are they called vinegar flies?

Vinegar flies are so named because of their attraction to the sour odor of fermentation. They are also called fruit flies or pomace flies. They are nuisance pests in homes, restaurants, grocery stores and any location with fermenting or rotting vegetative matter, where they often build up large populations.