Historical clue formulations

• Image formed by connecting this puzzle's circled letters from A to N and then back to A — 2019-04-18
• Word that must be added to 1-, 8-, 65- and 66-Across for their clues to make sense [with a visual hint in the grid] — 2017-06-21
• Insect that exhibits 44-/46-Across — 2015-04-15
• Swimming stroke — 2000-05-09
• Spitz stroke — 1998-08-23