$W={
	'A' => {
		'L' => {
			'D'=>99,
			'X'=>99,
			  },
		'C' =>{
			'E'=>99
			 },
		  }, 
	'X' => {
		'Q'=>{
			'O'=>99,
			},
		'T'=>{
			'U'=>99,
			},
		  }, 
	};

##</code><code>##

$X={
	'A' => {
			'D'=>99,
			'X'=>99,
			'E'=>99
		    },
	'X' => {
			'O'=>99,
			'U'=>99,
		    },
	};

##</code><code>##

printTree($W);	# just dumps HOHOH - could use data::dumper - removed
remove1($W,2);	# ie remove layer 2 ( counting from 1 )
print "--------------------\n";
printTree($W);

sub remove1
{
	my($refToHash)=shift;
	my($stage)=shift;
	
	foreach $a (keys %{$refToHash})
	{
		if($depth==$stage-1) # then we've hit the level before the level to be removed/
		{
			print "removing $a\n";
			foreach $b (keys %{$refToHash->{$a}})
			{
				$refToHash->{$b} = $refToHash->{$a}->{$b};
				delete($refToHash->{$a});
			}
		}
		else
		{
			$depth++;
			remove1($refToHash->{$a},$stage);
			$depth--;
		}
	}
}

##</code><code>##

 
perl delete_mid2.pl
A
 C
  E
 L
  D
  X
X
 Q
  O
 T
  U
removing C
removing L
removing Q
removing T
--------------------
A
 D
 E
 X
X
 O
 U

##</code><code>##

 
 sub deep_copy {
    my $this = shift;
    if (not ref $this) 
    {
      return $this;
    } 
    elsif(ref $this eq "HASH") 
    {
       return {map { $_ => deep_copy($this->{$_}) } keys %$this};
     } 
  }