Chironomids—large midges that live in landlocked bodies of water—are an essential pattern when targeting stillwater species or lake run trout. The pupa variation of this fly represents the stage in its life cycle where the insect moves up through the water column, using a gas bubble to lift them towards the surface, where they will emerge as an adult midge. This trapped air and gas gives the pupa a more silver and shiny appearance. Wings and legs also develop in the pupa stage, giving the fly a more complex silhouette than its larval counterpart. On warmer spring and summer days, you’ll find large concentrations of pupae towards the top of a lake, just before or during a noticeable hatch above the surface.

The pupa is also highly effective when nymphing, used as your top fly to place it in the mid to upper water column and you can effectively mimic both stages by fishing a Chirnomid Larva underneath the pupa.