Wing venation seems to fit Peterson’s description of deer flies, although apical cell R4 is more elongate than most, while cell R3 has a longer leading-edge margin. The rest of the veins look exactly like most deer flies, but I couldn't find any with that elongated R4. My specimen's wings also bear some resemblance to the Xylophagidae, but otherwise it's not at all similar.
It landed on the edge of my plate and sat quietly while I finished lunch and got my macro lens from the car.