This is just speculation but the description of using a bug is misleading. My guess is that they were describing a scorpion instead of a bug.
[Y]ou would also like to introduce an insect into one of the boxes with Zubaydah. As we understand it, you plan to inform Zubaydah that you are going to place a stinging insect into the box, but you will actually place a harmless insect in the box, such as a caterpillar. If you do so, to ensure you are outside the predicate death requirement, you must inform him that the insects will not have a sting that would produce death or severe pain. If, however, you were to place the insect in the box without informing him that you are doing so, you should not affirmatively lead him to believe that any insect is present which has a sting that could produce severe pain or suffering or even cause his death.
Note that the author describes an insect that would "Sting" not "bite". Bugs bite, bees and scorpions sting. While bed bugs and kissing bugs do bite and can transmit diseases, most people just kill the bug. No worries. So it was not a bug.
This is just speculation but the description of using a bug is misleading. My guess is that they were describing a scorpion instead of a bug.
"[Y]ou would also like to introduce an insect into one of the boxes with Zubaydah. "
Bugs
http://en.wikipedia.org/...
Later on the note describes an insect that would "Sting" not "bite". Bugs (Hemipterans) bite, bees and scorpions sting. While bed bugs and kissing bugs do bite and can transmit diseases, most people just kill the bug. No worries. So it was not a bug that they were planning to introduce.
However, in the middle east there are several dangerous Scorpion species.
Placing a scorpion in a coffin with a person would cause a lot of panic for anyone who grew up in the middle east. The interrogators could have shown the prisoner either a fattail scorpion
http://en.wikipedia.org/... Fat...tailed_scorpion
or a deathstalker
http://en.wikipedia.org/... Deathstalker
and placed any scorpion in the box. They wouldn't have to tell them that the creature was dangerous, most people would panic. Furthermore, a bee is hard to control, would sting once and just hurt. But a scorpions can sting and sting and sting. So the memo was probably meant to be misleading. It was written by scorpions for scorpions.