Does size matter?
Foam season means stonefly season has arrived. Hatches of skwalas and nemouras can start to bring fish to the surface. These early season insects are similar in color and often confused with each other, but differ in size dramatically.
Nemoura stones tend to hatch first and often overlap into the beginning of the skwalas. Nemouras are noticeably smaller, usually averaging about a size 12 2xl, but can be plus or minus a hook size.
Skwalas are longer and beefier. Often skwalas are long shank 10, and it's not uncommon to see some size 8's as well.
While nemouras will get some trout to feed on the surface it's really the skwala that will get them more excited on our rivers. I always pack a few smaller foam patterns to imitate a nemoura with me in the later part of February through spring just in-case, it has saved me more than once.
Skwala Stone - average approximate size is 10 (4x long)
Nemoura Stone - average approximate size is 12 (2x long)