This pattern imitates a caddis pupa that is about to hatch into an adult. When the pupa is ready to hatch, it fills with gas which buoys it quickly to the surface. There is a moment of hesitation, at which it is vulnerable, then the adult emerges and immediately flies off.
How to Fish
Dress the deer hair wing only. Use a floating line and a shallow nymph presentation. A wet-fly swing can also be effective. The Deep Sparkle Pupa is designed to be fished near the bottom, but many anglers just use this pattern for both deep and shallow presentations. When fishing it deep, present the fly near the bottom using the indicator or tight line presentations.