Yak bug


Defeat terrorism
March 9 2008

Every 3rd rock has 4 of these guys under it. This bug was kept in the boat - within 1 hour it had molted out and sprung wings!

A couple were seen flying around the walking bridge too - nowhere near clielm.


Sculpin Enterprises
Hi Chromer,

Those look like Skwalas. The males cannot fly. They wait under cover near the waters edge during the day. They come out from under cover at night (see www.washingtonflyfishing.com/gallery/showphoto.php?photo=12889&ppuser=3541) as new females emerge and pass along their genetic material (see www.washingtonflyfishing.com/gallery/showphoto.php?photo=12887&ppuser=3541). It can be quite a mob scene with several males trying to succeed with a single female. The flying versions would be slightly larger females.



Staff member

Your photo is of a Skwala, either S. americana or S. curvata, not sure which, and it is right on schedule. They are a member of family Perlodidae (Patterned Stoneflies), and commonly referred to as Skwalas, Medium Brown Stones, Spring Stones, etc.


New Member
I was on the Yak in Cle Elum on Saturday and saw the black versions size 10-12 and smaller ones size 16-18. There were certainly few and far between. I saw 2 of the large version and about 40 of the smaller ones.