Stocks opened lower Wednesday as the long-term Treasury yields hit their highest levels in 24 years. A successful auction of 10-year notes helped yields ease back from their intraday highs, but it wasn't enough to send the main equity benchmarks into positive territory.The 10-year Treasury yield fell slightly after this afternoon's bond action, but still closed up 1.5 basis points at 5.286%. The yield on the 30-year Treasury also pulled back from its early morning peak, but gained 3.0 basis points to 5.671%.As for stocks, the blue-chip Dow Jones Industrial Average fell 0.7% to 51,179, the broader S&P 500 shed…