Regarding the notion
scorpions commit
suicide when surrounded by inescapable flame, this is one of those legends akin to the lemming suicide
myth.
It's been proven scorpions are not affected by their own
poison. Scorpions do, however, really, really hate heat and fire and succumb very easily. Fire and high heat causes them great
panic and causes them to flail about with their tail, stinging at everything. They no doubt sometimes land a blow or two on themselves before kicking from the heat. Hence, it would appear a scorpion surrounded by fire stings itself to death but this is not the case.
Sources:
http://99.1911encyclopedia.org/S/SC/SCORPION.htm
http://www.bizarremag.com/ask_bizarre.php?id=208