Drosophila is a genus of small flies , belonging to the family Drosophilidae , whose members are often called `` fruit flies '' . Drosophila is a genus of small flies , belonging to the family Drosophilidae , whose members are often called `` fruit flies '' or more appropriately ( though less frequently ) pomace flies , vinegar flies , or wine flies , a reference to the characteristic of many species to linger around overripe or rotting fruit .