What are some examples of symbolism in Kafka's The Metamorphosis?

is the most famous work
by , published in 1915, about a man named
Gregor who spontaneously turns into an insect (Kafka intentionally
left the specific animal unclear).

While the story is a fairly
straightforward account of Gregor's transformation and fall from humanity, it does contain some
symbolism, which suffered somewhat from the necessary translation to English. The first and most
important is Gregor's new form, that of an inhuman creature: in the original German, the
descriptive word literally means "unclean animal" or "vermin," but further
description and common conception make Gregor some form of giant beetle. This represents his
isolation in the world, and how both his job and family refuse to appreciate his hard work. In
fact, his first reaction to his transformation is frustration, since he is going to be late for
work, and only later does he realize his true fate. His family, meanwhile, are all irritated
that they will need to work to support themselves, instead of living off his wages; although
they are disgusted at his new form, they are equally disgusted that he has abandoned them,
although not by choice.

Another symbol, drawing on the first, is Gregor's new
form having a shell, making him an invertebrate creature relying on an exoskeleton. The term
"spineless," meaning coward, is implied early, when Gregor thinks about being late for
his job:

...the firm's errand boy would've waited for the
five o'clock train and reported the news of his absence long ago. He was the boss's minion,
without backbone or intelligence.

And yet Gregor himself
is spineless, because he will not quit his job for his own sake. Later, when his father throws
an apple at him, it gets lodged in his back, possibly cracking his exoskeleton and making him
even more "spineless."

There are other symbols in the text, each
referring to an aspect of Gregor's life and legacy, which in the end is only enough to free his
family through death.