What discerns the two here? Would a male Funereal be darker on the forewing?

but it's not easy to explain. There are several differences, many are "average" in nature and overlap, but some are more constant. One character that is often obvious and easy is the dark postmedian "rectangle" (or sometimes more fat "hourglass" shaped) next to the inner (lower) margin of the front wing. It is almost always distinctly shorter and most often more contrasting on E. tristis.

The pale subapical patch is usually pronounced on E. funeralis but less often so on E. tristis, but it's presence isn't a reliable character alone. However, if you look closely, the structure of the pale area is usually different on the two species.

Of course males and females tend to look different from one another in both species, so that complicates things too. Lighter and more contrasting pattern on females in both species.

The white markings on the underside of the hind wing are different on each species too (more developed on E. tristis, and often entirely absent on E. funeralis, but obviously that doesn't help here. Other pattern elements are positioned differently as well. Since they have different host plants, they are often found in habitats where the host plant of the other isn't found (especially females). However, E. funeralis is such a wanderer, that it could turn up almost anywhere.

I think they are harder to tell apart in Texas than elsewhere, but I think E. funeralis is much more likely to be seen in Texas.

I'll have to start looking at male forewings more closely between these two.