I’m trying to figure out how to refer to the rhetorical device in which one refers to a collective as an individual member of that group, e.g. ’the Hun’ for soldiers of the German Empire during the first World War, or ’the Bantoo’ or ’the Hindoo’ in older ethnographic writing. An example, from the movie Patton:
'Now there’s another thing I want you to remember. I don’t want to get any messages saying that we are holding our position. We’re not holding anything. Let the Hun do that. We are advancing constantly and we’re not interested in holding onto anything except the enemy. We're going to hold onto him by the nose and we're going to kick him in the ass. We're going to kick the hell out of him all the time and we're gonna go through him like crap through a goose.’
The general is referring to German soldiers collectively, but through an imagined individual (perhaps because for military purposes, there's little point in differentiating among the individuals?).
It seems like this might be a subcategory of synecdoche.