Skwala stoneflies belong to the family Perlodidae also known as the Large Springflies. Skwalas are the first hatch of big insects in rivers, and in the Prince George area they hatch during the first half of May. You may see some as early as late April. As they hatch early most rivers are not fishable yet, but they do provide the first opportunity to fish dry flies.
The males are around 15mm in the length and the females 20-25mm. Although fairly large these stoneflies are much smaller than Salmonflies and Goldenstones that hatch later in the season.
Here is an attempt to imitate this insect using a Stimulator in Skwala colours.
Originator: Danie Erasmus
Hook: #8 TMC 200R BL
Thread: 6/0 Rusty brown
Tail: Olive deer hair
Abdomen: Brown olive Antron dry fly dubbing
Ribbing: Yellow embroidery thread
Abdomen hackle: Blue dun hackle
Wing: Olive deer hair
Sighter: Bright orange craft foam
Thorax hackle: Yellow grizzly
Thorax: Amber Antron dry fly dubbing