Like most sarcophagids, adult females of W. magnifica deposit live larvae, each laying up to about 160.
The larvae moult twice as they mature. When mature they stop feeding and leave the wound, falling onto the substrate into which they try to bury. The outer larval skin hardens and darkens into a lozenge-shaped puparium. This is actually the cuticle of the last larval instar and, within its protection, the pupa forms.
The adult emerges from the pupa within about one week if not in diapause.