Fifty percent of a Spring Creek’s aquatic insects are diptera, about 50,000 of them per square yard!*
The family diptera contains several non biting chironomids, in various colors, all year around, but intensely in the summer through early autumn.
Expect to see midges (diptera) all year. If there isn’t a larger food organism available, the trout have to eat them.
The most effective midge pupa imitation I know of is Al's Rat.
I imitate adults with Griffith’s Gnat.
My Spring Creek Fly box always contains Gnats and Rats. in sizes 18 through 28.