September's the month for daddy long legs. Get a few early Aug then they tend to peak this month before the first frosts kill them off. Fish especially trout love them and can be caught quiet readily on a imitation daddy long legs fly. In Ireland they use the live adults in a method called dapping which basically involves hooking the fly gently so it's still alive then lowering it onto the waters surface so that it looks like it's landed naturally to fool the trout into taking the bait.
Steve