The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
Costa: The costa (denoted C) is the first (anterior) major longitudinal wing vein. In caddisflies, it forms most or all of the front edge of each wing.
These other words reference the same concept: costal, costal vein, vein C, C, C vein.
