The simian-faced Irishman was Thomas Nast's trademark depiction of "Paddy" who was often depicted with a flask of liquor in his back pocket.
Other minorities did not fare much better in Nast cartoons. The caption of this catoon was "The Ignorant Vote" which implied that the Black Republican vote in the South was the equivalent of the Irish Democrat vote in the North.
Ironically, Nast was himself an immigrant from Germany.....An ethnic group that was not particularly liked in the Union Army where German Americans were disparaged as being incompetents and cowards especially after the XIth Corps' unfortunate encounter with Stonewall Jackson at the Battle of Chancellorsville.
Of course, by the 20th Century, German Americans were considered God's gift to the U.S. military.
On a more positive note, Nast contibuted the modern day American image of Santa Claus, the Republican Elephant and the Democrat Donkey.
