Possibly a Grevillia Looper caterpillar. The caterpillar was housed in the round end of the flower (ovary?) I've added a photo of the flower comb that the "ovary" fell off.
I see no evidence that this caterpillar is missing 3 pairs of prolegs, so no evidence that it is in Geometridae. The only Geometrid caterpillar that I know lives inside its food fruit is Chloroclystis filata, and that caterpillar has a regular pattern along its body. An off-white body with a brown collar looks more like some Tortrid and Tineid caterpillars.