This Skwala nymph still has a couple months left to go before hatching, but it's still a good representative of its species, which was extremely abundant in my sample for a stonefly of this size. It's obvious why the Yakima is known for its Skwala hatch.
Sadly, the largest mayflies of the early season come in small quantities. Siphloplecton basale matches the impressive size of the Ephemera drakes which follow two months later, but it does not match their numbers. It is common on one of my favorite rivers to see ten to fifteen of these elegant drakes dancing over a riffle in the early Spring. They are difficult to miss in the air, but on the water that quantity cannot get the trout or the angler excited.
There are rumors of fishable Siphloplecton days, but I know none of the details. They might be locally important in places angler-entomologists have yet to visit in the prime months, an unsung local treasure like Baetisca laurentina.
I went to great comical lengths to swipe this spinner from the air with a little aquarium net I carry with me while I'm fishing. Siphloplecton basale spinners fly fast and high over the riffles, and there are never very many of them, so they're difficult to catch.