In Lord of The Flies, what does The Lord of the Flies symbolize literally and figuratively?

William Golding uses the book's title- Lord of
the Flies- symbolically and gives the reader an immediate unpleasant
sensation at the thought of flies. Initially it seems a strange title for a novel about
a group of schoolboys who are stranded on an island without any adult supervision and
adds that sense of apprehension as the story proceeds. There are various symbols
including the "pig's head on a stick" (ch 8) as Simon recognizes it to be and the
symbols collectively allow the boys to represent a microcosm of society as they struggle
with their realization that they do need to do the right and the best thing, but as
children they also have a childish need to have fun and act
impulsively. 

The conch shell represents the closest thing
to democracy and is used to call the boys to order, have meetings, make decisions and
hear anyone who needs to speak. It gives Ralph confidence as leader and as its power
diminishes so too does Ralph's confidence in himself as leader. Piggy's glasses add to
the boys' perception of good decision making as they are used to start the fire and,
when they are misused by Jack, not only Piggy but the whole group is affected. The
signal fire is the boys' hope for rescue and a reason to keep trying to survive because
as Jack ironically states in chapter 2, "we're not
savages." 

The Lord of the Flies itself then is a sharp
contrast to all the boys' best efforts and defies everything childlike, innocent and
good. Literally, it is the head of the pig which Jack killed so that they can have a
feast and invite everyone to it.  Symbolically for Jack, it proves his ability to
embrace his compulsive side and gain some measure of control. It effectively gives him
permission to behave erratically, irresponsibly and brutally. On Jack's instructions the
boys sharpen a stick and he impales the head on the stick and leaves the head as a gift
for the personified beast which the boys are convinced that they have
seen.

For Simon, the Lord of the Flies is the image which
he encounters and discredits. Simon is not easily fooled and the pig's head is
threatened by Simon's attempts to warn the others about the beast. It reminds Simon that
the island is for fun and that he cannot stop the fun. It is clear that the Lord of the
Flies version of "fun" is not at all childlike and is violent, vindictive and
merciless.