I came across this website http://iz.carnegiemnh.org/cranefly/ on Craneflies in PA - yes a whole website dedicated to the topic in some detail.

Which species, presumably one of the aquatic species, of cranefly is it that trout favor, and which patterns are effective imitations? Also what is the size range we might expect to find them this time of the year?

I some folks are doing well with Walt's Worm, which I assume is being taken as a Cranefly larva. This is a pretty large fly typically tied 10 to 16. Are there smaller Craneflies and if so, which patterns are folks finding to work well to imitate them.

The reason I ask is that fish are reportedly feeding on size 26 craneflies and midges one of the streams I fish in Eastern PA. I didn't think Craneflies came this small so I am a bit confused.