If you look at the Arduino println() documentation you'll see that it appends a carriage return and linefeed at the end. So in decimal you will end up with 65 (A), 13 (CR) and 10 (LF) which in binary translates to:
01000001 00001101 00001010
Async serial data is sent LSB first so that becomes:
10000010 10110000 01010000
Your signal is idle high so the start bit will be 0 and the stop bit will be 1 so adding that to each byte and you end up with:
0100000101 0101100001 0010100001
It's a bit hard to work out the exact timing from your diagram but that seems to at least roughly match up and should give you an idea where some of the extra bits come from and why they are re-ordered. The Wikipedia link provided by Kvegaoro gives a lot of good background information on async serial data.