【英语时差8,16】死虫子和僵硬的手

（单词翻译）

Everyone has found a dead or dying roach, spider or beetle¹ on its back with its legs up in the air. Somehow, it seems, bugs³ decide to flip⁴ themselves over in order to die. But why should they?   

Some entomologists suggest that the reason so many dead bugs are found on their backs is in the way their legs work -- or cease to work. When a bug² is alive and walking, it generally is very stable, since it has a body suspended between multiple legs. When they die, however, those mobile and actively⁵ balancing legs return to what is called the "position of flexion."

"Position of flexion" is a name for what a group of muscles do when there is no tension in them at all -- that is, when they are dead. If you relax your hand, for example, you will see that the fingers do not lie flat; they naturally curl about halfway⁶ in. Although still alive, that half-curled shape approximates the position of flexion for the human hand.

For some species of bug, a similar curled-in shape is the position of flexion in death. If you imagine your hand walking along on its fingers and then curling them all inward, you can see how likely it is that the whole structure would roll over onto its back -- as happens with bugs.