Intelligence of a fearful tragedy reached the city on Saturday. The victims are the wife and child of Capt. Dennis MAHONEY, who have been killed by the husband and father on board the ship "Lizzie Fennell" at Callao. All parties are well known in this city and Portland where they belong, the unfortunate woman, as well as the husband, having relatives residing here. The ship is owned by Mr. T. McCARTHY, F. SWEENEY and T. FURLONG and is a new vessel. Capt MAHONEY, who is a good citizen and trustworthy man when in his sober senses, was the reverse when under the influence of liquor, and when he committed the horrible crime, he was maddened with liquor. The cabin of his ship was the scene of the tragedy, the helpless victims having their throats cut before assistance could reach them. The wretched man was arrested, and so great was the anger of the populace at the butchery, that to save him from being lynched, he was taken on board a British man of war. Many of our Portland readers remember Annie MONTAGUE who, with one of her two children, is now buried near the capital of Peru, struck down early in life by a husband's hand. Capt. John DWYER left by train Sunday night to take charge of the ship now without a captain.