This detail of an image provided Thursday, June 18, 2009 by Chicago's Abraham Lincoln Book Shop Inc. shows part of an Aug. 1863 glass plate negative of President Abraham Lincoln at a portrait studio in Washington, D.C. The photo shows a house fly on Lincoln's trouser leg just left and below his right knee. It proves that President Barack Obama, who swatted and killed a fly during an interview Tuesday, isn't the only president to have had an encounter with a fly. AP Photo logo AP Photo 4 months ago

This detail of an image provided Thursday, June 18, 2009 by Chicago's Abraham Lincoln Book Shop Inc. shows part of an Aug. 1863 glass plate negative of President Abraham Lincoln at a portrait studio in Washington, D.C. The photo shows a house fly on Lincoln's trouser leg just left and below his right knee. It proves that President Barack Obama, who swatted and killed a fly during an interview Tuesday, isn't the only president to have had an encounter with a fly.