St. Louis, April 12. - A special dispatch f rom Key West says: News has reached Havana of the massacre of flfty reconcentrados at Escambra. Permission was given the reconcentrados in Santa Clara to return to their devastated homes. They issued from the city and camped at Escambra, erecting palm huts. Trusting the Spaniards, they began anew the struggle for existence. To escape starvatiqn the fugitives killed several head of cattle out of a drove of hundreds which the Spaniards have never been able to take to the towns, so closely are they guarded by the insurgents. This was made the pretext for a massacre, and Thursday night a troop ot Spaniards dashed into the camp, rode down the fleeing men and women and slashed them to death. A few escaped into the woods, but fifty were killed and many more wounded. The reconcentrados are now without hope. They believe that the Spaniards' promises were but a plot to inveigle them into the fields so that they might be slaughtered. Fear a Massacre at Havana. Havana, April 12.- There are still in Havana over 600 Americans, who rushed panic-stricken to the British consulate because it was rumored that the volunteers were bent on massacre. The British pro-consul, Arthur Aroztegui, assured them that they would be protected. Erastus Wllson, an American dentist, has published in La Lucha a letter against General Lee in favor of Spain, Mr. Wilson says that he remains in Havana certain that nothing will happen to him. General Pando arrived from Camaguey to confer with General Blanco. The volunteers in Havana are parading the streets day and night.