On the 9th of September, 1945, when the machine was experiencing problems, an investigation showed that there was a moth trapped between the points of Relay #70, in Panel F.
The operators removed the moth and affixed it to the log. (See the picture below.) The entry reads: "First actual case of bug being found."
The word went out that they had "debugged" the machine and the term "debugging a computer program" was born.
