Preheat griddle until water dances across the top. In a large bowl, combine flour, blue corn meal, baking powder, sugar and salt. In a medium bowl, whisk together milk, vinegar, eggs and butter. Add wet ingredients to the dry ones. Mix until just blended; some lumps will remain. Gently stir in blueberries. Lightly spray griddle and pour ¼ cup for each pancake. Cook until it just puffs and begins to bubble. Turn and cook until lightly browned. Serve with butter and a good maple syrup. Makes 16-18 pancakes.