Well, the things you learn: I’ve been calling these fruit flies my whole life, but at some point it came to my attention that they are also known as vinegar flies. I don’t know if this is specific to certain regions, but BugGuide.net has them listed primarily as vinegar with the fruit being under “Other Common Names.” As far as I can tell, from a cursory, unscientific internet search, fruit flies is more common, but there are differing views held on that. Wikipedia goes so far as to say they are sometimes known as “small fruit flies” (which I say is ridiculous), but then the Drosophila page brings up the fact that there is another group, Tephritidae, “which are also called fruit flies (sometimes referred to as “true fruit flies”).” Now perhaps that is why some people think it is proper to call them vinegar flies, i.e. to avoid confusion. That’s just my own supposition, and I’m sure a more knowledgeable person has a real and succinct explanation for this. Alas, it won’t be a foreseeable me, because for the time being, my interest and patience for researching this topic has run aground. To move on, maybe I’ll post a photo of a tephritid fly and call it a “large vinegar fly.”