Stapelia blooms in late autumn and did again this October. I caught a nice group of green bottle flies on this fully open blossom. Bugguide uses the name Lucilia sericata for this species, while "Phaenicia sericata" rolls off the tongue of Hodgkins on Bones ("phaenicia sericata. early stage of colonization. no eggs or maggots present. Oh look! one of them is dead") with charming regularity. Not sure which is most correct or if there is a difference. Nevertheless, yes there IS a dead one there on the flower.
Stapelia puts out a stink very much like that of rotting flesh, attracting flies to the flowers where they can't help themselves from laying copious amounts of eggs. The eggs hatch and the maggots are doomed. Yay. Natural pest control for your estate, just position the plants far from outdoor eating areas.
I have an interesting story about flies and milkweed, but not now. Suffice it to say that green bottle flies also frequent milkweed to their doom. Bwa ha ha.