You may have found the information you are seeking by now. Just in case not, or in case you don't already have this information, Egidio arrived in New York on April 19 1916 on board the America, with son Andrew, from Naples. His age was 44, place of residence Gelsi, Italy, nationality Italian, name Egidio Ciaccia.
In the 1930 census, Andrew (born 11 Nov 1901 Italy), Mary (born c 1902 Ohio, of Italian parents) and their three children are living in Cleveland. Mary may have been Mary Testa, born 4 Feb 1902 in Cleveland, to Giuseppe Testa, 33, and Filomena Valiante, 32, both born Italy.
Have you looked at Andrew's naturalization documents (seems to be 1926-27) to see if there is anything helpful re Egidio there? I looked for Egidio in FamilySearch but didn't see any records for him in South America, although there are records of his arrival in the US and census references.
There is some discussion of resources re Italian immigration to South America at
http://www.italiangenealogy.com/forum/topic6634.html