Try this link
It has a chart for insects that are hatching in Indiana by month and the fly that matches them. They are selling the flies there but you can look at the patterns and tie them (or reasonable imitations) yourself.
Have fun. My advice? Concentrate on not scaring the fish (approaching the water and during casting) and in presenting the fly the way a natural insect would look to the trout and worry less about the exact type of fly you have.