Black Midge Pupa. Like its more mature stage the Black Midge Pupa is a requirement for those serious trout fisherman. Midge in the Pupa stage are particularly vulnerable to Trout as they are emerging to the surface of the water to hatch into its final stage, the adult Midge. Midges are so populous across Canada and the US that there is almost always Black Midge Pupa available making them easy prey to the hungry trout.