This time the curiosity is that the name is feminine (Cacilda). The flag is black and white: a white border surrounds a thin black border which in turn surrounds a white panel with a narrow black diagonal from lower hoist to upper fly. Two letters are in this panel, A in upper hoist, H in lower fly. I don't know about the A (the name initial of Mrs. Cacilda's husband? Sheer speculation here), but H is likely to refer to Henriques.